diff --git a/src/Humanizer.Tests.Shared/CollectionHumanizeTests.cs b/src/Humanizer.Tests.Shared/CollectionHumanizeTests.cs
index 6feb304f2..cc6a1aed2 100644
--- a/src/Humanizer.Tests.Shared/CollectionHumanizeTests.cs
+++ b/src/Humanizer.Tests.Shared/CollectionHumanizeTests.cs
@@ -78,7 +78,7 @@ public void HumanizeDefaultsToToString()
         [Fact]
         public void HumanizeUsesStringDisplayFormatter()
         {
-            var humanized = _testCollection.Humanize(sc => string.Format("SomeObject #{0} - {1}", sc.SomeInt, sc.SomeString));
+            var humanized = _testCollection.Humanize(sc => $"SomeObject #{sc.SomeInt} - {sc.SomeString}");
             Assert.Equal("SomeObject #1 - One, SomeObject #2 - Two, and SomeObject #3 - Three", humanized);
         }
 
@@ -92,7 +92,7 @@ public void HumanizeUsesObjectDisplayFormatter()
         [Fact]
         public void HumanizeUsesStringDisplayFormatterWhenSeparatorIsProvided()
         {
-            var humanized = _testCollection.Humanize(sc => string.Format("SomeObject #{0} - {1}", sc.SomeInt, sc.SomeString), "or");
+            var humanized = _testCollection.Humanize(sc => $"SomeObject #{sc.SomeInt} - {sc.SomeString}", "or");
             Assert.Equal("SomeObject #1 - One, SomeObject #2 - Two, or SomeObject #3 - Three", humanized);
         }
 
diff --git a/src/Humanizer/Bytes/ByteSize.cs b/src/Humanizer/Bytes/ByteSize.cs
index 655604242..b1c35d34c 100644
--- a/src/Humanizer/Bytes/ByteSize.cs
+++ b/src/Humanizer/Bytes/ByteSize.cs
@@ -309,7 +309,7 @@ private string ToString(string format, IFormatProvider provider, bool toSymbol)
                                               ? "0"
                                               : formattedLargeWholeNumberValue;
 
-            return string.Format("{0} {1}", formattedLargeWholeNumberValue, toSymbol ? GetLargestWholeNumberSymbol(provider) : GetLargestWholeNumberFullWord(provider));
+            return $"{formattedLargeWholeNumberValue} {(toSymbol ? GetLargestWholeNumberSymbol(provider) : GetLargestWholeNumberFullWord(provider))}";
         }
 
         /// <summary>
diff --git a/src/Humanizer/Localisation/NumberToWords/AfrikaansNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/AfrikaansNumberToWordsConverter.cs
index 6d3276d5a..bada2b604 100644
--- a/src/Humanizer/Localisation/NumberToWords/AfrikaansNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/AfrikaansNumberToWordsConverter.cs
@@ -45,32 +45,32 @@ private string Convert(int number, bool isOrdinal)
 
             if (number < 0)
             {
-                return string.Format("minus {0}", Convert(-number));
+                return $"minus {Convert(-number)}";
             }
 
             var parts = new List<string>();
 
             if ((number / 1000000000) > 0)
             {
-                parts.Add(string.Format("{0} miljard", Convert(number / 1000000000)));
+                parts.Add($"{Convert(number / 1000000000)} miljard");
                 number %= 1000000000;
             }
 
             if ((number / 1000000) > 0)
             {
-                parts.Add(string.Format("{0} miljoen", Convert(number / 1000000)));
+                parts.Add($"{Convert(number / 1000000)} miljoen");
                 number %= 1000000;
             }
 
             if ((number / 1000) > 0)
             {
-                parts.Add(string.Format("{0} duisend", Convert(number / 1000)));
+                parts.Add($"{Convert(number / 1000)} duisend");
                 number %= 1000;
             }
 
             if ((number / 100) > 0)
             {
-                parts.Add(string.Format("{0} honderd", Convert(number / 100)));
+                parts.Add($"{Convert(number / 100)} honderd");
                 number %= 100;
             }
 
@@ -94,11 +94,11 @@ private string Convert(int number, bool isOrdinal)
                     var lastPart = TensMap[number / 10];
                     if ((number % 10) > 0)
                     {
-                        lastPart = string.Format("{0} en {1}", GetUnitValue(number % 10, false), isOrdinal ? GetUnitValue(lastPartValue, isOrdinal) : lastPart);
+                        lastPart = $"{GetUnitValue(number % 10, false)} en {(isOrdinal ? GetUnitValue(lastPartValue, isOrdinal) : lastPart)}";
                     }
                     else if ((number % 10) == 0)
                     {
-                        lastPart = string.Format("{0}{1}{2}", parts.Count > 0 ? "en " : "", lastPart, isOrdinal ? "ste" : "");
+                        lastPart = $"{(parts.Count > 0 ? "en " : "")}{lastPart}{(isOrdinal ? "ste" : "")}";
                     }
                     else if (isOrdinal)
                     {
diff --git a/src/Humanizer/Localisation/NumberToWords/ArabicNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/ArabicNumberToWordsConverter.cs
index 51576cf80..df476f5ab 100644
--- a/src/Humanizer/Localisation/NumberToWords/ArabicNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/ArabicNumberToWordsConverter.cs
@@ -25,7 +25,7 @@ public override string Convert(long number, GrammaticalGender gender, bool addAn
 
             if (number < 0)
             {
-                return string.Format("ناقص {0}", Convert(-number, gender));
+                return $"ناقص {Convert(-number, gender)}";
             }
 
             var result = string.Empty;
@@ -114,7 +114,7 @@ public override string Convert(long number, GrammaticalGender gender, bool addAn
                     {
                         if (result != string.Empty)
                         {
-                            result = string.Format("{0} {1}", "و", result);
+                            result = $"{"و"} {result}";
                         }
 
                         if (groupNumber != 2)
@@ -123,21 +123,21 @@ public override string Convert(long number, GrammaticalGender gender, bool addAn
                             {
                                 if (groupNumber >= 3 && groupNumber <= 10)
                                 {
-                                    result = string.Format("{0} {1}", PluralGroups[groupLevel], result);
+                                    result = $"{PluralGroups[groupLevel]} {result}";
                                 }
                                 else
                                 {
-                                    result = string.Format("{0} {1}", result != string.Empty ? AppendedGroups[groupLevel] : Groups[groupLevel], result);
+                                    result = $"{(result != string.Empty ? AppendedGroups[groupLevel] : Groups[groupLevel])} {result}";
                                 }
                             }
                             else
                             {
-                                result = string.Format("{0} {1}", Groups[groupLevel], result);
+                                result = $"{Groups[groupLevel]} {result}";
                             }
                         }
                     }
 
-                    result = string.Format("{0} {1}", process, result);
+                    result = $"{process} {result}";
                 }
 
                 groupLevel++;
diff --git a/src/Humanizer/Localisation/NumberToWords/ArmenianNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/ArmenianNumberToWordsConverter.cs
index 1e493eb82..09e9cfa9f 100644
--- a/src/Humanizer/Localisation/NumberToWords/ArmenianNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/ArmenianNumberToWordsConverter.cs
@@ -52,39 +52,39 @@ private string ConvertImpl(long number, bool isOrdinal)
 
             if (number < 0)
             {
-                return string.Format("մինուս {0}", ConvertImpl(-number, isOrdinal));
+                return $"մինուս {ConvertImpl(-number, isOrdinal)}";
             }
 
             var parts = new List<string>();
 
             if ((number / 1000000000000000000) > 0)
             {
-                parts.Add(string.Format("{0} քվինտիլիոն", Convert(number / 1000000000000000000)));
+                parts.Add($"{Convert(number / 1000000000000000000)} քվինտիլիոն");
                 number %= 1000000000000000000;
             }
 
             if ((number / 1000000000000000) > 0)
             {
-                parts.Add(string.Format("{0} կվադրիլիոն", Convert(number / 1000000000000000)));
+                parts.Add($"{Convert(number / 1000000000000000)} կվադրիլիոն");
                 number %= 1000000000000000;
             }
 
             if ((number / 1000000000000) > 0)
 
             {
-                parts.Add(string.Format("{0} տրիլիոն", Convert(number / 1000000000000)));
+                parts.Add($"{Convert(number / 1000000000000)} տրիլիոն");
                 number %= 1000000000000;
             }
 
             if ((number / 1000000000) > 0)
             {
-                parts.Add(string.Format("{0} միլիարդ", Convert(number / 1000000000)));
+                parts.Add($"{Convert(number / 1000000000)} միլիարդ");
                 number %= 1000000000;
             }
 
             if ((number / 1000000) > 0)
             {
-                parts.Add(string.Format("{0} միլիոն", Convert(number / 1000000)));
+                parts.Add($"{Convert(number / 1000000)} միլիոն");
                 number %= 1000000;
             }
 
@@ -96,7 +96,7 @@ private string ConvertImpl(long number, bool isOrdinal)
                 }
                 else
                 {
-                    parts.Add(string.Format("{0} հազար", Convert(number / 1000)));
+                    parts.Add($"{Convert(number / 1000)} հազար");
                 }
 
                 number %= 1000;
@@ -110,7 +110,7 @@ private string ConvertImpl(long number, bool isOrdinal)
                 }
                 else
                 {
-                    parts.Add(string.Format("{0} հարյուր", Convert(number / 100)));
+                    parts.Add($"{Convert(number / 100)} հարյուր");
                 }
 
                 number %= 100;
@@ -127,7 +127,7 @@ private string ConvertImpl(long number, bool isOrdinal)
                     var lastPart = TensMap[number / 10];
                     if ((number % 10) > 0)
                     {
-                        lastPart += string.Format("{0}", GetUnitValue(number % 10, isOrdinal));
+                        lastPart += $"{GetUnitValue(number % 10, isOrdinal)}";
                     }
                     else if (isOrdinal)
                     {
diff --git a/src/Humanizer/Localisation/NumberToWords/AzerbaijaniNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/AzerbaijaniNumberToWordsConverter.cs
index 2299d3907..7877943c7 100644
--- a/src/Humanizer/Localisation/NumberToWords/AzerbaijaniNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/AzerbaijaniNumberToWordsConverter.cs
@@ -35,34 +35,34 @@ public override string Convert(long input)
 
             if (number < 0)
             {
-                return string.Format("mənfi {0}", Convert(-number));
+                return $"mənfi {Convert(-number)}";
             }
 
             var parts = new List<string>();
 
             if ((number / 1000000000) > 0)
             {
-                parts.Add(string.Format("{0} milyard", Convert(number / 1000000000)));
+                parts.Add($"{Convert(number / 1000000000)} milyard");
                 number %= 1000000000;
             }
 
             if ((number / 1000000) > 0)
             {
-                parts.Add(string.Format("{0} milyon", Convert(number / 1000000)));
+                parts.Add($"{Convert(number / 1000000)} milyon");
                 number %= 1000000;
             }
 
             var thousand = (number / 1000);
             if (thousand > 0)
             {
-                parts.Add(string.Format("{0} min", thousand > 1 ? Convert(thousand) : "").Trim());
+                parts.Add($"{(thousand > 1 ? Convert(thousand) : "")} min".Trim());
                 number %= 1000;
             }
 
             var hundred = (number / 100);
             if (hundred > 0)
             {
-                parts.Add(string.Format("{0} yüz", hundred > 1 ? Convert(hundred) : "").Trim());
+                parts.Add($"{(hundred > 1 ? Convert(hundred) : "")} yüz".Trim());
                 number %= 100;
             }
 
@@ -107,7 +107,7 @@ public override string ConvertToOrdinal(int number)
                 word = word.Substring(0, word.Length - 1);
             }
 
-            return string.Format("{0}{1}", word, wordSuffix);
+            return $"{word}{wordSuffix}";
         }
     }
 }
diff --git a/src/Humanizer/Localisation/NumberToWords/BanglaNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/BanglaNumberToWordsConverter.cs
index 7c84ec985..ef5c65e0a 100644
--- a/src/Humanizer/Localisation/NumberToWords/BanglaNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/BanglaNumberToWordsConverter.cs
@@ -75,32 +75,32 @@ public override string Convert(long input)
 
             if (number < 0)
             {
-                return string.Format("ঋণাত্মক {0}", Convert(-number));
+                return $"ঋণাত্মক {Convert(-number)}";
             }
 
             var parts = new List<string>();
 
             if ((number / 10000000) > 0)
             {
-                parts.Add(string.Format("{0} কোটি", Convert(number / 10000000)));
+                parts.Add($"{Convert(number / 10000000)} কোটি");
                 number %= 10000000;
             }
 
             if ((number / 100000) > 0)
             {
-                parts.Add(string.Format("{0} লক্ষ", Convert(number / 100000)));
+                parts.Add($"{Convert(number / 100000)} লক্ষ");
                 number %= 100000;
             }
 
             if ((number / 1000) > 0)
             {
-                parts.Add(string.Format("{0} হাজার", Convert(number / 1000)));
+                parts.Add($"{Convert(number / 1000)} হাজার");
                 number %= 1000;
             }
 
             if ((number / 100) > 0)
             {
-                parts.Add(string.Format("{0}", HundredsMap[number / 100]));
+                parts.Add($"{HundredsMap[number / 100]}");
                 number %= 100;
             }
 
diff --git a/src/Humanizer/Localisation/NumberToWords/BrazilianPortugueseNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/BrazilianPortugueseNumberToWordsConverter.cs
index 3a9d678ed..bff907392 100644
--- a/src/Humanizer/Localisation/NumberToWords/BrazilianPortugueseNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/BrazilianPortugueseNumberToWordsConverter.cs
@@ -29,7 +29,7 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
 
             if (number < 0)
             {
-                return string.Format("menos {0}", Convert(Math.Abs(number), gender));
+                return $"menos {Convert(Math.Abs(number), gender)}";
             }
 
             var parts = new List<string>();
@@ -38,8 +38,8 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
             {
                 // gender is not applied for billions
                 parts.Add(number / 1000000000 >= 2
-                    ? string.Format("{0} bilhões", Convert(number / 1000000000, GrammaticalGender.Masculine))
-                    : string.Format("{0} bilhão", Convert(number / 1000000000, GrammaticalGender.Masculine)));
+                    ? $"{Convert(number / 1000000000, GrammaticalGender.Masculine)} bilhões"
+                    : $"{Convert(number / 1000000000, GrammaticalGender.Masculine)} bilhão");
 
                 number %= 1000000000;
             }
@@ -48,8 +48,8 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
             {
                 // gender is not applied for millions
                 parts.Add(number / 1000000 >= 2
-                    ? string.Format("{0} milhões", Convert(number / 1000000, GrammaticalGender.Masculine))
-                    : string.Format("{0} milhão", Convert(number / 1000000, GrammaticalGender.Masculine)));
+                    ? $"{Convert(number / 1000000, GrammaticalGender.Masculine)} milhões"
+                    : $"{Convert(number / 1000000, GrammaticalGender.Masculine)} milhão");
 
                 number %= 1000000;
             }
@@ -57,7 +57,7 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
             if ((number / 1000) > 0)
             {
                 // gender is not applied for thousands
-                parts.Add(number / 1000 == 1 ? "mil" : string.Format("{0} mil", Convert(number / 1000, GrammaticalGender.Masculine)));
+                parts.Add(number / 1000 == 1 ? "mil" : $"{Convert(number / 1000, GrammaticalGender.Masculine)} mil");
                 number %= 1000;
             }
 
@@ -92,7 +92,7 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
                     var lastPart = PortugueseTensMap[number / 10];
                     if ((number % 10) > 0)
                     {
-                        lastPart += string.Format(" e {0}", ApplyGender(PortugueseUnitsMap[number % 10], gender));
+                        lastPart += $" e {ApplyGender(PortugueseUnitsMap[number % 10], gender)}";
                     }
 
                     parts.Add(lastPart);
diff --git a/src/Humanizer/Localisation/NumberToWords/CentralKurdishNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/CentralKurdishNumberToWordsConverter.cs
index 7f42786e7..39ba14c8c 100644
--- a/src/Humanizer/Localisation/NumberToWords/CentralKurdishNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/CentralKurdishNumberToWordsConverter.cs
@@ -19,7 +19,7 @@ public override string Convert(long number)
 
             if (number < 0)
             {
-                return string.Format("نێگەتیڤ {0}", Convert(-number));
+                return $"نێگەتیڤ {Convert(-number)}";
             }
 
             if (number == 0)
@@ -29,11 +29,11 @@ public override string Convert(long number)
 
             var kurdishGroupsMap = new Dictionary<long, Func<long, string>>
             {
-                {(long)Math.Pow(10, 15), n => string.Format("{0} کوادریلیۆن", Convert(n)) },
-                {(long)Math.Pow(10, 12), n => string.Format("{0} تریلیۆن", Convert(n)) },
-                {(long)Math.Pow(10, 9), n => string.Format("{0} میلیارد", Convert(n)) },
-                {(long)Math.Pow(10, 6), n => string.Format("{0} میلیۆن", Convert(n)) },
-                {(long)Math.Pow(10, 3), n => string.Format("{0} هەزار", Convert(n)) },
+                {(long)Math.Pow(10, 15), n => $"{Convert(n)} کوادریلیۆن"},
+                {(long)Math.Pow(10, 12), n => $"{Convert(n)} تریلیۆن"},
+                {(long)Math.Pow(10, 9), n => $"{Convert(n)} میلیارد"},
+                {(long)Math.Pow(10, 6), n => $"{Convert(n)} میلیۆن"},
+                {(long)Math.Pow(10, 3), n => $"{Convert(n)} هەزار"},
                 {(long)Math.Pow(10, 2), n => KurdishHundredsMap[n]}
             };
 
@@ -68,7 +68,7 @@ public override string Convert(long number)
         public override string ConvertToOrdinal(int number)
         {
             var word = Convert(number);
-            return string.Format("{0}{1}", word, IsVowel(word[word.Length - 1]) ? "یەم" : "ەم");
+            return $"{word}{(IsVowel(word[word.Length - 1]) ? "یەم" : "ەم")}";
         }
 
         private bool IsVowel(char c)
diff --git a/src/Humanizer/Localisation/NumberToWords/ChineseNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/ChineseNumberToWordsConverter.cs
index 2ae778f2d..d79116f19 100644
--- a/src/Humanizer/Localisation/NumberToWords/ChineseNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/ChineseNumberToWordsConverter.cs
@@ -27,7 +27,7 @@ private string Convert(long number, bool isOrdinal, bool isSpecial)
 
             if (number < 0)
             {
-                return string.Format("负 {0}", Convert(-number, false, false));
+                return $"负 {Convert(-number, false, false)}";
             }
 
             var parts = new List<string>();
@@ -100,10 +100,10 @@ private string Convert(long number, bool isOrdinal, bool isSpecial)
                 }
                 else
                 {
-                    var lastPart = string.Format("{0}十", UnitsMap[number / 10]);
+                    var lastPart = $"{UnitsMap[number / 10]}十";
                     if ((number % 10) > 0)
                     {
-                        lastPart += string.Format("{0}", UnitsMap[number % 10]);
+                        lastPart += $"{UnitsMap[number % 10]}";
                     }
 
                     parts.Add(lastPart);
@@ -119,7 +119,7 @@ private string Convert(long number, bool isOrdinal, bool isSpecial)
 
             if (isOrdinal)
             {
-                toWords = string.Format("第 {0}", toWords);
+                toWords = $"第 {toWords}";
             }
 
             return toWords;
diff --git a/src/Humanizer/Localisation/NumberToWords/CroatianNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/CroatianNumberToWordsConverter.cs
index b9f181dc0..26028fbdf 100644
--- a/src/Humanizer/Localisation/NumberToWords/CroatianNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/CroatianNumberToWordsConverter.cs
@@ -30,7 +30,7 @@ public override string Convert(long input)
 
             if (number < 0)
             {
-                return string.Format("- {0}", Convert(-number));
+                return $"- {Convert(-number)}";
             }
 
             var parts = new List<string>();
@@ -99,7 +99,7 @@ public override string Convert(long input)
 
                     if (units > 0)
                     {
-                        parts.Add(string.Format(" {0}", UnitsMap[units]));
+                        parts.Add($" {UnitsMap[units]}");
                     }
                 }
             }
diff --git a/src/Humanizer/Localisation/NumberToWords/DutchNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/DutchNumberToWordsConverter.cs
index 67b3a15df..72cea2b73 100644
--- a/src/Humanizer/Localisation/NumberToWords/DutchNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/DutchNumberToWordsConverter.cs
@@ -46,7 +46,7 @@ public override string Convert(long input)
 
             if (number < 0)
             {
-                return string.Format("min {0}", Convert(-number));
+                return $"min {Convert(-number)}";
             }
 
             var word = "";
diff --git a/src/Humanizer/Localisation/NumberToWords/EnglishNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/EnglishNumberToWordsConverter.cs
index d58801bb6..2fe2d0869 100644
--- a/src/Humanizer/Localisation/NumberToWords/EnglishNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/EnglishNumberToWordsConverter.cs
@@ -44,50 +44,50 @@ private string Convert(long number, bool isOrdinal, bool addAnd = true)
 
             if (number < 0)
             {
-                return string.Format("minus {0}", Convert(-number));
+                return $"minus {Convert(-number)}";
             }
 
             var parts = new List<string>();
 
             if ((number / 1000000000000000000) > 0)
             {
-                parts.Add(string.Format("{0} quintillion", Convert(number / 1000000000000000000)));
+                parts.Add($"{Convert(number / 1000000000000000000)} quintillion");
                 number %= 1000000000000000000;
             }
 
             if ((number / 1000000000000000) > 0)
             {
-                parts.Add(string.Format("{0} quadrillion", Convert(number / 1000000000000000)));
+                parts.Add($"{Convert(number / 1000000000000000)} quadrillion");
                 number %= 1000000000000000;
             }
 
             if ((number / 1000000000000) > 0)
             {
-                parts.Add(string.Format("{0} trillion", Convert(number / 1000000000000)));
+                parts.Add($"{Convert(number / 1000000000000)} trillion");
                 number %= 1000000000000;
             }
 
             if ((number / 1000000000) > 0)
             {
-                parts.Add(string.Format("{0} billion", Convert(number / 1000000000)));
+                parts.Add($"{Convert(number / 1000000000)} billion");
                 number %= 1000000000;
             }
 
             if ((number / 1000000) > 0)
             {
-                parts.Add(string.Format("{0} million", Convert(number / 1000000)));
+                parts.Add($"{Convert(number / 1000000)} million");
                 number %= 1000000;
             }
 
             if ((number / 1000) > 0)
             {
-                parts.Add(string.Format("{0} thousand", Convert(number / 1000)));
+                parts.Add($"{Convert(number / 1000)} thousand");
                 number %= 1000;
             }
 
             if ((number / 100) > 0)
             {
-                parts.Add(string.Format("{0} hundred", Convert(number / 100)));
+                parts.Add($"{Convert(number / 100)} hundred");
                 number %= 100;
             }
 
@@ -107,7 +107,7 @@ private string Convert(long number, bool isOrdinal, bool addAnd = true)
                     var lastPart = TensMap[number / 10];
                     if ((number % 10) > 0)
                     {
-                        lastPart += string.Format("-{0}", GetUnitValue(number % 10, isOrdinal));
+                        lastPart += $"-{GetUnitValue(number % 10, isOrdinal)}";
                     }
                     else if (isOrdinal)
                     {
diff --git a/src/Humanizer/Localisation/NumberToWords/FarsiNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/FarsiNumberToWordsConverter.cs
index 7399aac39..2c0b23b26 100644
--- a/src/Humanizer/Localisation/NumberToWords/FarsiNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/FarsiNumberToWordsConverter.cs
@@ -13,7 +13,7 @@ public override string Convert(long number)
         {
             if (number < 0)
             {
-                return string.Format("منفی {0}", Convert(-number));
+                return $"منفی {Convert(-number)}";
             }
 
             if (number == 0)
@@ -23,12 +23,12 @@ public override string Convert(long number)
 
             var farsiGroupsMap = new Dictionary<long, Func<long, string>>
             {
-                {(long)Math.Pow(10, 18), n => string.Format("{0} تریلیون", Convert(n)) },
-                {(long)Math.Pow(10, 15), n => string.Format("{0} بیلیارد", Convert(n)) },
-                {(long)Math.Pow(10, 12), n => string.Format("{0} بیلیون", Convert(n)) },
-                {(long)Math.Pow(10, 9), n => string.Format("{0} میلیارد", Convert(n)) },
-                {(long)Math.Pow(10, 6), n => string.Format("{0} میلیون", Convert(n)) },
-                {(long)Math.Pow(10, 3), n => string.Format("{0} هزار", Convert(n)) },
+                {(long)Math.Pow(10, 18), n => $"{Convert(n)} تریلیون"},
+                {(long)Math.Pow(10, 15), n => $"{Convert(n)} بیلیارد"},
+                {(long)Math.Pow(10, 12), n => $"{Convert(n)} بیلیون"},
+                {(long)Math.Pow(10, 9), n => $"{Convert(n)} میلیارد"},
+                {(long)Math.Pow(10, 6), n => $"{Convert(n)} میلیون"},
+                {(long)Math.Pow(10, 3), n => $"{Convert(n)} هزار"},
                 {(long)Math.Pow(10, 2), n => FarsiHundredsMap[n]}
             };
 
@@ -74,7 +74,7 @@ public override string ConvertToOrdinal(int number)
             }
 
             var word = Convert(number);
-            return string.Format("{0}{1}", word, word.EndsWith("ی") ? " ام" : "م");
+            return $"{word}{(word.EndsWith("ی") ? " ام" : "م")}";
         }
     }
 }
diff --git a/src/Humanizer/Localisation/NumberToWords/FinnishNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/FinnishNumberToWordsConverter.cs
index 6d322170f..cf06d4f57 100644
--- a/src/Humanizer/Localisation/NumberToWords/FinnishNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/FinnishNumberToWordsConverter.cs
@@ -24,7 +24,7 @@ public override string Convert(long input)
 
             if (number < 0)
             {
-                return string.Format("miinus {0}", Convert(-number));
+                return $"miinus {Convert(-number)}";
             }
 
             if (number == 0)
@@ -38,7 +38,7 @@ public override string Convert(long input)
             {
                 parts.Add(number / 1000000000 == 1
                     ? "miljardi "
-                    : string.Format("{0}miljardia ", Convert(number / 1000000000)));
+                    : $"{Convert(number / 1000000000)}miljardia ");
 
                 number %= 1000000000;
             }
@@ -47,7 +47,7 @@ public override string Convert(long input)
             {
                 parts.Add(number / 1000000 == 1
                     ? "miljoona "
-                    : string.Format("{0}miljoonaa ", Convert(number / 1000000)));
+                    : $"{Convert(number / 1000000)}miljoonaa ");
 
                 number %= 1000000;
             }
@@ -56,7 +56,7 @@ public override string Convert(long input)
             {
                 parts.Add(number / 1000 == 1
                     ? "tuhat "
-                    : string.Format("{0}tuhatta ", Convert(number / 1000)));
+                    : $"{Convert(number / 1000)}tuhatta ");
 
                 number %= 1000;
             }
@@ -65,19 +65,19 @@ public override string Convert(long input)
             {
                 parts.Add(number / 100 == 1
                     ? "sata"
-                    : string.Format("{0}sataa", Convert(number / 100)));
+                    : $"{Convert(number / 100)}sataa");
 
                 number %= 100;
             }
 
             if (number >= 20 && (number / 10) > 0)
             {
-                parts.Add(string.Format("{0}kymmentä", Convert(number / 10)));
+                parts.Add($"{Convert(number / 10)}kymmentä");
                 number %= 10;
             }
             else if (number > 10 && number < 20)
             {
-                parts.Add(string.Format("{0}toista", UnitsMap[number % 10]));
+                parts.Add($"{UnitsMap[number % 10]}toista");
             }
 
             if (number > 0 && number <= 10)
@@ -109,36 +109,36 @@ private string ToOrdinal(int number, bool useExceptions)
 
             if ((number / 1000000000) > 0)
             {
-                parts.Add(string.Format("{0}miljardis", (number / 1000000000) == 1 ? "" : ToOrdinal(number / 1000000000, true)));
+                parts.Add($"{((number / 1000000000) == 1 ? "" : ToOrdinal(number / 1000000000, true))}miljardis");
                 number %= 1000000000;
             }
 
             if ((number / 1000000) > 0)
             {
-                parts.Add(string.Format("{0}miljoonas", (number / 1000000) == 1 ? "" : ToOrdinal(number / 1000000, true)));
+                parts.Add($"{((number / 1000000) == 1 ? "" : ToOrdinal(number / 1000000, true))}miljoonas");
                 number %= 1000000;
             }
 
             if ((number / 1000) > 0)
             {
-                parts.Add(string.Format("{0}tuhannes", (number / 1000) == 1 ? "" : ToOrdinal(number / 1000, true)));
+                parts.Add($"{((number / 1000) == 1 ? "" : ToOrdinal(number / 1000, true))}tuhannes");
                 number %= 1000;
             }
 
             if ((number / 100) > 0)
             {
-                parts.Add(string.Format("{0}sadas", (number / 100) == 1 ? "" : ToOrdinal(number / 100, true)));
+                parts.Add($"{((number / 100) == 1 ? "" : ToOrdinal(number / 100, true))}sadas");
                 number %= 100;
             }
 
             if (number >= 20 && (number / 10) > 0)
             {
-                parts.Add(string.Format("{0}kymmenes", ToOrdinal(number / 10, true)));
+                parts.Add($"{ToOrdinal(number / 10, true)}kymmenes");
                 number %= 10;
             }
             else if (number > 10 && number < 20)
             {
-                parts.Add(string.Format("{0}toista", GetOrdinalUnit(number % 10, true)));
+                parts.Add($"{GetOrdinalUnit(number % 10, true)}toista");
             }
 
             if (number > 0 && number <= 10)
diff --git a/src/Humanizer/Localisation/NumberToWords/GermanNumberToWordsConverterBase.cs b/src/Humanizer/Localisation/NumberToWords/GermanNumberToWordsConverterBase.cs
index c21ba1d8d..e4574ac02 100644
--- a/src/Humanizer/Localisation/NumberToWords/GermanNumberToWordsConverterBase.cs
+++ b/src/Humanizer/Localisation/NumberToWords/GermanNumberToWordsConverterBase.cs
@@ -57,7 +57,7 @@ public override string Convert(long number, GrammaticalGender gender, bool addAn
                     var units = number % 10;
                     if (units > 0)
                     {
-                        parts.Add(string.Format("{0}und", UnitsMap[units]));
+                        parts.Add($"{UnitsMap[units]}und");
                     }
 
                     parts.Add(GetTens(number / 10));
diff --git a/src/Humanizer/Localisation/NumberToWords/HebrewNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/HebrewNumberToWordsConverter.cs
index 7ecda3774..383323c00 100644
--- a/src/Humanizer/Localisation/NumberToWords/HebrewNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/HebrewNumberToWordsConverter.cs
@@ -48,7 +48,7 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
 
             if (number < 0)
             {
-                return string.Format("מינוס {0}", Convert(-number, gender));
+                return $"מינוס {Convert(-number, gender)}";
             }
 
             if (number == 0)
@@ -99,7 +99,7 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
                 {
                     var unit = Convert(number % 10, gender);
                     unit = unit.Replace("יי", "י");
-                    unit = string.Format("{0} {1}", unit, gender == GrammaticalGender.Masculine ? "עשר" : "עשרה");
+                    unit = $"{unit} {(gender == GrammaticalGender.Masculine ? "עשר" : "עשרה")}";
                     if (appendAnd)
                     {
                         unit = "ו" + unit;
@@ -117,7 +117,7 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
                     else
                     {
                         var unit = Convert(number % 10, gender);
-                        parts.Add(string.Format("{0} ו{1}", tenUnit, unit));
+                        parts.Add($"{tenUnit} ו{unit}");
                     }
                 }
             }
diff --git a/src/Humanizer/Localisation/NumberToWords/JapaneseNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/JapaneseNumberToWordsConverter.cs
index 3c8cbc4e4..8e8a396e6 100644
--- a/src/Humanizer/Localisation/NumberToWords/JapaneseNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/JapaneseNumberToWordsConverter.cs
@@ -28,7 +28,7 @@ private string ConvertImpl(long number, bool isOrdinal)
 
             if (number < 0)
             {
-                return string.Format("マイナス {0}", ConvertImpl(-number, false));
+                return $"マイナス {ConvertImpl(-number, false)}";
             }
 
             var parts = new List<string>();
@@ -59,7 +59,7 @@ private string ConvertImpl(long number, bool isOrdinal)
 
             if (isOrdinal)
             {
-                toWords = string.Format("{0}番目", toWords);
+                toWords = $"{toWords}番目";
             }
 
             return toWords;
diff --git a/src/Humanizer/Localisation/NumberToWords/KoreanNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/KoreanNumberToWordsConverter.cs
index 32fbde9b3..36c4d16ee 100644
--- a/src/Humanizer/Localisation/NumberToWords/KoreanNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/KoreanNumberToWordsConverter.cs
@@ -57,7 +57,7 @@ private string ConvertImpl(long number, bool isOrdinal)
 
             if (number < 0)
             {
-                return string.Format("마이너스 {0}", ConvertImpl(-number, false));
+                return $"마이너스 {ConvertImpl(-number, false)}";
             }
 
             var parts = new List<string>();
@@ -88,7 +88,7 @@ private string ConvertImpl(long number, bool isOrdinal)
 
             if (isOrdinal)
             {
-                toWords = string.Format("{0}번째", toWords);
+                toWords = $"{toWords}번째";
             }
 
             return toWords;
diff --git a/src/Humanizer/Localisation/NumberToWords/NorwegianBokmalNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/NorwegianBokmalNumberToWordsConverter.cs
index 8739033f3..692f2de28 100644
--- a/src/Humanizer/Localisation/NumberToWords/NorwegianBokmalNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/NorwegianBokmalNumberToWordsConverter.cs
@@ -45,7 +45,7 @@ private string Convert(int number, bool isOrdinal, GrammaticalGender gender)
 
             if (number < 0)
             {
-                return string.Format("minus {0}", Convert(-number, isOrdinal, gender));
+                return $"minus {Convert(-number, isOrdinal, gender)}";
             }
 
             if (number == 1)
@@ -120,7 +120,7 @@ private string Convert(int number, bool isOrdinal, GrammaticalGender gender)
                     var lastPart = TensMap[number / 10];
                     if ((number % 10) > 0)
                     {
-                        lastPart += string.Format("{0}", GetUnitValue(number % 10, isOrdinal));
+                        lastPart += $"{GetUnitValue(number % 10, isOrdinal)}";
                     }
                     else if (isOrdinal)
                     {
diff --git a/src/Humanizer/Localisation/NumberToWords/PortugueseNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/PortugueseNumberToWordsConverter.cs
index 776bb804a..f9e111cdb 100644
--- a/src/Humanizer/Localisation/NumberToWords/PortugueseNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/PortugueseNumberToWordsConverter.cs
@@ -29,7 +29,7 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
 
             if (number < 0)
             {
-                return string.Format("menos {0}", Convert(Math.Abs(number), gender));
+                return $"menos {Convert(Math.Abs(number), gender)}";
             }
 
             var parts = new List<string>();
@@ -39,7 +39,7 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
                 // gender is not applied for billions
                 parts.Add(number / 1000000000 == 1
                     ? "mil milhões"
-                    : string.Format("{0} mil milhões", Convert(number / 1000000000)));
+                    : $"{Convert(number / 1000000000)} mil milhões");
 
                 number %= 1000000000;
             }
@@ -48,8 +48,8 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
             {
                 // gender is not applied for millions
                 parts.Add(number / 1000000 >= 2
-                    ? string.Format("{0} milhões", Convert(number / 1000000, GrammaticalGender.Masculine))
-                    : string.Format("{0} milhão", Convert(number / 1000000, GrammaticalGender.Masculine)));
+                    ? $"{Convert(number / 1000000, GrammaticalGender.Masculine)} milhões"
+                    : $"{Convert(number / 1000000, GrammaticalGender.Masculine)} milhão");
 
                 number %= 1000000;
             }
@@ -57,7 +57,7 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
             if ((number / 1000) > 0)
             {
                 // gender is not applied for thousands
-                parts.Add(number / 1000 == 1 ? "mil" : string.Format("{0} mil", Convert(number / 1000, GrammaticalGender.Masculine)));
+                parts.Add(number / 1000 == 1 ? "mil" : $"{Convert(number / 1000, GrammaticalGender.Masculine)} mil");
                 number %= 1000;
             }
 
@@ -92,7 +92,7 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
                     var lastPart = PortugueseTensMap[number / 10];
                     if ((number % 10) > 0)
                     {
-                        lastPart += string.Format(" e {0}", ApplyGender(PortugueseUnitsMap[number % 10], gender));
+                        lastPart += $" e {ApplyGender(PortugueseUnitsMap[number % 10], gender)}";
                     }
 
                     parts.Add(lastPart);
@@ -115,8 +115,8 @@ public override string ConvertToOrdinal(int number, GrammaticalGender gender)
             if ((number / 1000000000) > 0)
             {
                 parts.Add(number / 1000000000 == 1
-                    ? string.Format("{0} {1}", ApplyOrdinalGender("milésimo", gender), ApplyOrdinalGender("milionésimo", gender))
-                    : string.Format("{0} {1} {2}", Convert(number / 1000000000), ApplyOrdinalGender("milésimo", gender), ApplyOrdinalGender("milionésimo", gender)));
+                    ? $"{ApplyOrdinalGender("milésimo", gender)} {ApplyOrdinalGender("milionésimo", gender)}"
+                    : $"{Convert(number / 1000000000)} {ApplyOrdinalGender("milésimo", gender)} {ApplyOrdinalGender("milionésimo", gender)}");
 
                 number %= 1000000000;
             }
diff --git a/src/Humanizer/Localisation/NumberToWords/SerbianCyrlNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/SerbianCyrlNumberToWordsConverter.cs
index f1f1a3c06..4a231ec9c 100644
--- a/src/Humanizer/Localisation/NumberToWords/SerbianCyrlNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/SerbianCyrlNumberToWordsConverter.cs
@@ -31,7 +31,7 @@ public override string Convert(long input)
 
             if (number < 0)
             {
-                return string.Format("- {0}", Convert(-number));
+                return $"- {Convert(-number)}";
             }
 
             var parts = new List<string>();
@@ -101,7 +101,7 @@ public override string Convert(long input)
 
                     if (units > 0)
                     {
-                        parts.Add(string.Format(" {0}", UnitsMap[units]));
+                        parts.Add($" {UnitsMap[units]}");
                     }
                 }
             }
diff --git a/src/Humanizer/Localisation/NumberToWords/SerbianNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/SerbianNumberToWordsConverter.cs
index 4ffd20b5b..4a916cd5f 100644
--- a/src/Humanizer/Localisation/NumberToWords/SerbianNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/SerbianNumberToWordsConverter.cs
@@ -30,7 +30,7 @@ public override string Convert(long input)
 
             if (number < 0)
             {
-                return string.Format("- {0}", Convert(-number));
+                return $"- {Convert(-number)}";
             }
 
             var parts = new List<string>();
@@ -99,7 +99,7 @@ public override string Convert(long input)
 
                     if (units > 0)
                     {
-                        parts.Add(string.Format(" {0}", UnitsMap[units]));
+                        parts.Add($" {UnitsMap[units]}");
                     }
                 }
             }
diff --git a/src/Humanizer/Localisation/NumberToWords/SlovenianNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/SlovenianNumberToWordsConverter.cs
index 8fe8fdddf..cda9e7033 100644
--- a/src/Humanizer/Localisation/NumberToWords/SlovenianNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/SlovenianNumberToWordsConverter.cs
@@ -30,7 +30,7 @@ public override string Convert(long input)
 
             if (number < 0)
             {
-                return string.Format("minus {0}", Convert(-number));
+                return $"minus {Convert(-number)}";
             }
 
             var parts = new List<string>();
@@ -97,7 +97,7 @@ public override string Convert(long input)
                     var units = number % 10;
                     if (units > 0)
                     {
-                        parts.Add(string.Format("{0}in", UnitsMap[units]));
+                        parts.Add($"{UnitsMap[units]}in");
                     }
 
                     parts.Add(TensMap[number / 10]);
diff --git a/src/Humanizer/Localisation/NumberToWords/SwedishNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/SwedishNumberToWordsConverter.cs
index 325c3420a..67d5eea3f 100644
--- a/src/Humanizer/Localisation/NumberToWords/SwedishNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/SwedishNumberToWordsConverter.cs
@@ -42,7 +42,7 @@ public override string Convert(long input, GrammaticalGender gender, bool addAnd
 
             if (number < 0)
             {
-                return string.Format("minus {0}", Convert(-number, gender));
+                return $"minus {Convert(-number, gender)}";
             }
 
             var word = "";
diff --git a/src/Humanizer/Localisation/NumberToWords/TamilNumberToWordsConverter.cs b/src/Humanizer/Localisation/NumberToWords/TamilNumberToWordsConverter.cs
index 6ffe99bd9..5071a4424 100644
--- a/src/Humanizer/Localisation/NumberToWords/TamilNumberToWordsConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/TamilNumberToWordsConverter.cs
@@ -40,19 +40,19 @@ private string ConvertImpl(long number, bool isOrdinal)
                 return GetUnitValue(0, isOrdinal);
 
             if (number < 0)
-                return string.Format("கழித்தல் {0}", Convert(-number));
+                return $"கழித்தல் {Convert(-number)}";
 
             var parts = new List<string>();
 
             if ((number / 1000000000000000000) > 0)
             {
-                parts.Add(string.Format("{0} quintillion", Convert(number / 1000000000000000000)));
+                parts.Add($"{Convert(number / 1000000000000000000)} quintillion");
                 number %= 1000000000000000000;
             }
 
             if ((number / 1000000000000000) > 0)
             {
-                parts.Add(string.Format("{0} quadrillion", Convert(number / 1000000000000000)));
+                parts.Add($"{Convert(number / 1000000000000000)} quadrillion");
                 number %= 1000000000000000;
             }
 
@@ -126,7 +126,7 @@ private static string GetTensValue(long number, bool isOrdinal, bool isThousand
                     else
                         lastPart += "த்து ";
                     
-                    if (!isThousand) lastPart += string.Format("{0}", GetUnitValue(number % 10, isOrdinal));
+                    if (!isThousand) lastPart += $"{GetUnitValue(number % 10, isOrdinal)}";
                 }
                 else if (number % 10 == 0)
                 {
diff --git a/src/Humanizer/Localisation/NumberToWords/TurkishNumberToWordConverter.cs b/src/Humanizer/Localisation/NumberToWords/TurkishNumberToWordConverter.cs
index d2f4c7714..574d12985 100644
--- a/src/Humanizer/Localisation/NumberToWords/TurkishNumberToWordConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/TurkishNumberToWordConverter.cs
@@ -42,52 +42,52 @@ public override string Convert(long input)
 
             if (number < 0)
             {
-                return string.Format("eksi {0}", Convert(-number));
+                return $"eksi {Convert(-number)}";
             }
 
             var parts = new List<string>();
 
             if ((number / 1000000000000000000) > 0)
             {
-                parts.Add(string.Format("{0} kentilyon", Convert(number / 1000000000000000000)));
+                parts.Add($"{Convert(number / 1000000000000000000)} kentilyon");
                 number %= 1000000000000000000;
             }
 
             if ((number / 1000000000000000) > 0)
             {
-                parts.Add(string.Format("{0} katrilyon", Convert(number / 1000000000000000)));
+                parts.Add($"{Convert(number / 1000000000000000)} katrilyon");
                 number %= 1000000000000000;
             }
 
             if ((number / 1000000000000) > 0)
             {
-                parts.Add(string.Format("{0} trilyon", Convert(number / 1000000000000)));
+                parts.Add($"{Convert(number / 1000000000000)} trilyon");
                 number %= 1000000000000;
             }
 
             if ((number / 1000000000) > 0)
             {
-                parts.Add(string.Format("{0} milyar", Convert(number / 1000000000)));
+                parts.Add($"{Convert(number / 1000000000)} milyar");
                 number %= 1000000000;
             }
 
             if ((number / 1000000) > 0)
             {
-                parts.Add(string.Format("{0} milyon", Convert(number / 1000000)));
+                parts.Add($"{Convert(number / 1000000)} milyon");
                 number %= 1000000;
             }
 
             var thousand = (number / 1000);
             if (thousand > 0)
             {
-                parts.Add(string.Format("{0} bin", thousand > 1 ? Convert(thousand) : "").Trim());
+                parts.Add($"{(thousand > 1 ? Convert(thousand) : "")} bin".Trim());
                 number %= 1000;
             }
 
             var hundred = (number / 100);
             if (hundred > 0)
             {
-                parts.Add(string.Format("{0} yüz", hundred > 1 ? Convert(hundred) : "").Trim());
+                parts.Add($"{(hundred > 1 ? Convert(hundred) : "")} yüz".Trim());
                 number %= 100;
             }
 
@@ -132,7 +132,7 @@ public override string ConvertToOrdinal(int number)
                 word = word.Substring(0, word.Length - 1);
             }
 
-            return string.Format("{0}{1}", word, wordSuffix);
+            return $"{word}{wordSuffix}";
         }
 
         public override string ConvertToTuple(int number)
@@ -155,7 +155,7 @@ public override string ConvertToTuple(int number)
                         }
                     }
 
-                    return string.Format("{0}{1}", word, wordSuffix);
+                    return $"{word}{wordSuffix}";
             }
         }
     }
diff --git a/src/Humanizer/Localisation/NumberToWords/UzbekCyrlNumberToWordConverter.cs b/src/Humanizer/Localisation/NumberToWords/UzbekCyrlNumberToWordConverter.cs
index c0873c6b0..13000c831 100644
--- a/src/Humanizer/Localisation/NumberToWords/UzbekCyrlNumberToWordConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/UzbekCyrlNumberToWordConverter.cs
@@ -19,7 +19,7 @@ public override string Convert(long input)
             var number = (int)input;
             if (number < 0)
             {
-                return string.Format("минус {0}", Convert(-number, true));
+                return $"минус {Convert(-number, true)}";
             }
 
             return Convert(number, true);
@@ -94,7 +94,7 @@ public override string ConvertToOrdinal(int number)
                 i = 1;
             }
 
-            return string.Format("{0}{1}", word, OrdinalSuffixes[i]);
+            return $"{word}{OrdinalSuffixes[i]}";
         }
     }
 }
diff --git a/src/Humanizer/Localisation/NumberToWords/UzbekLatnNumberToWordConverter.cs b/src/Humanizer/Localisation/NumberToWords/UzbekLatnNumberToWordConverter.cs
index 117cfcc50..0563b9322 100644
--- a/src/Humanizer/Localisation/NumberToWords/UzbekLatnNumberToWordConverter.cs
+++ b/src/Humanizer/Localisation/NumberToWords/UzbekLatnNumberToWordConverter.cs
@@ -19,7 +19,7 @@ public override string Convert(long input)
             var number = (int)input;
             if (number < 0)
             {
-                return string.Format("minus {0}", Convert(-number, true));
+                return $"minus {Convert(-number, true)}";
             }
 
             return Convert(number, true);
@@ -94,7 +94,7 @@ public override string ConvertToOrdinal(int number)
                 i = 1;
             }
 
-            return string.Format("{0}{1}", word, OrdinalSuffixes[i]);
+            return $"{word}{OrdinalSuffixes[i]}";
         }
     }
 }
diff --git a/src/Humanizer/Localisation/Ordinalizers/RomanianOrdinalizer.cs b/src/Humanizer/Localisation/Ordinalizers/RomanianOrdinalizer.cs
index 989ba1902..ffbd02977 100644
--- a/src/Humanizer/Localisation/Ordinalizers/RomanianOrdinalizer.cs
+++ b/src/Humanizer/Localisation/Ordinalizers/RomanianOrdinalizer.cs
@@ -29,10 +29,10 @@ public override string Convert(int number, string numberString, GrammaticalGende
 
             if (gender == GrammaticalGender.Feminine)
             {
-                return string.Format("a {0}-a", numberString);
+                return $"a {numberString}-a";
             }
 
-            return string.Format("al {0}-lea", numberString);
+            return $"al {numberString}-lea";
 
         }
     }
diff --git a/src/Humanizer/ToQuantityExtensions.cs b/src/Humanizer/ToQuantityExtensions.cs
index 204a98945..173976d4a 100644
--- a/src/Humanizer/ToQuantityExtensions.cs
+++ b/src/Humanizer/ToQuantityExtensions.cs
@@ -116,7 +116,7 @@ private static string ToQuantity(this string input, long quantity, ShowQuantityA
                 return string.Format(formatProvider, "{0} {1}", quantity.ToString(format, formatProvider), transformedInput);
             }
 
-            return string.Format("{0} {1}", quantity.ToWords(), transformedInput);
+            return $"{quantity.ToWords()} {transformedInput}";
         }
         
         /// <summary>