# .NET convert number to string representation (1 to one, 2 to two, etc…)

Is there a built in method in .NET to convert a number to the string representation of the number? For example, 1 becomes one, 2 becomes two, etc.

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Here is a more complete/improved solution based on a couple ideas also posted here. Includes grammar/hyphen fixes, and optional capitalization, long support, support for zero, and yet still very succinct (VB.Net):

``````Function NumberToCapitalizedWords(ByVal n As Long) As String
Return New System.Globalization.CultureInfo("en-US", False).TextInfo.ToTitleCase(NumberToWords(n))
End Function

Function NumberToWords(ByVal n As Long) As String
Return LTrim(NumberToWords(n, False, False))
End Function

Function NumberToWords(ByVal n As Long, ByVal recursed As Boolean, ByVal iesLast As Boolean) As String
If (n < 0) Then
Return "negative" + NumberToWords(-n, False, False)
ElseIf (n = 0) Then
If recursed Then
Return ""
End If
Return "zero"
ElseIf (n < 20) Then
Return If(iesLast, "-", " ") + New String() {"one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"}(n - 1)
ElseIf (n < 100) Then
Return " " + New String() {"twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"}(n  10 - 2) + NumberToWords(n Mod 10, True, True)
ElseIf (n < 1000) Then

Return NumberToWords(n  100, True, False) + " hundred" + NumberToWords(n Mod 100, True, False)
Else
Dim log1000 As Integer = Math.Floor(Math.Log(n, 1000))
Return NumberToWords(n  PowerNoFloat(1000, log1000), True, False) + " " + New String() {"thousand", "million", "billion", "trillion", "quadrillion", "quintillion"}(log1000 - 1) + NumberToWords(n Mod PowerNoFloat(1000, log1000), True, False)
End If

End Function

Function PowerNoFloat(ByRef base As Long, ByRef power As Integer) As Long
If power < 0 Then
Return 0
End If
Dim result As Long = 1
For i As Integer = 1 To power
result *= base
Next
Return result
End Function
`````` 2022-06-07 10 楼

Another naasking, version in VB.NET if any one is interested! Had to use the floor function to round properly..

`````` Public Function NumberToText(n As Integer) As String
Dim a As String() = {"One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"}
Dim tens As String() = {"Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy",
"Eighty", "Ninety"}

If (n < 0) Then
Return "Minus " + NumberToText(-n)
ElseIf (n = 0) Then
Return ""
ElseIf (n <= 19) Then
Return a(n - 1) + " "
ElseIf (n <= 99) Then
Return tens(Math.Floor(n / 10) - 2) + " " + NumberToText(n Mod 10)
ElseIf (n <= 199) Then
Return "One Hundred " + NumberToText(n Mod 100)
ElseIf (n <= 999) Then
Return NumberToText(Math.Floor(n / 100)) + "Hundreds " + NumberToText(n Mod 100)
ElseIf (n <= 1999) Then
Return "One Thousand " + NumberToText(n Mod 1000)
ElseIf (n <= 999999) Then
Return NumberToText(Math.Floor(n / 1000)) + "Thousands " + NumberToText(n Mod 1000)
ElseIf (n <= 1999999) Then
Return "One Million " + NumberToText(n Mod 1000000)
ElseIf (n <= 999999999) Then
Return NumberToText(Math.Floor(n / 1000000)) + "Millions " + NumberToText(n Mod 1000000)
ElseIf (n <= 1999999999) Then
Return "One Billion " + NumberToText(n Mod 1000000000)
Else
Return NumberToText(Math.Floor(n / 1000000000)) + "Billions " + NumberToText(n Mod 1000000000)
End If

End Function
`````` 2022-06-07 9 楼

A conversion from integer to long form English... I could write that ;-) is a pretty good article on the topic:

``````using System;

public class NumberToEnglish {
private static string[] onesMapping =
new string[] {
"Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine",
"Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"
};
private static string[] tensMapping =
new string[] {
"Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"
};
private static string[] groupMapping =
new string[] {
"Hundred", "Thousand", "Million", "Billion", "Trillion"
};

private static void Main(string[] args) {
Console.WriteLine(EnglishFromNumber(long.Parse(args)));
}

private static string EnglishFromNumber(int number) {
return EnglishFromNumber((long) number);
}

private static string EnglishFromNumber(long number) {
if ( number == 0 ) {
return onesMapping[number];
}

string sign = "Positive";
if ( number < 0 ) {
sign = "Negative";
number = Math.Abs(number);
}

string retVal = null;
int group = 0;
while(number > 0) {
int numberToProcess = (int) (number % 1000);
number = number / 1000;

string groupDescription = ProcessGroup(numberToProcess);
if ( groupDescription != null ) {
if ( group > 0 ) {
retVal = groupMapping[group] + " " + retVal;
}
retVal = groupDescription + " " + retVal;
}

group++;
}

return sign + " " + retVal;
}

private static string ProcessGroup(int number) {
int tens = number % 100;
int hundreds = number / 100;

string retVal = null;
if ( hundreds > 0 ) {
retVal = onesMapping[hundreds] + " " + groupMapping;
}
if ( tens > 0 ) {
if ( tens < 20 ) {
retVal += ((retVal != null) ? " " : "") + onesMapping[tens];
} else {
int ones = tens % 10;
tens = (tens / 10) - 2; // 20's offset

retVal += ((retVal != null) ? " " : "") + tensMapping[tens];

if ( ones > 0 ) {
retVal += ((retVal != null) ? " " : "") + onesMapping[ones];
}
}
}

return retVal;
}
}
`````` 2022-06-07 8 楼

Here's my refined version of the first answer. I hope it's useful.

``````/// <summary>
/// Converts an <see cref="int"/> to its textual representation
/// </summary>
/// <param name="num">
/// The number to convert to text
/// </param>
/// <returns>
/// A textual representation of the given number
/// </returns>
public static string ToText(this int num)
{
StringBuilder result;

if (num < 0)
{
return string.Format("Minus {0}", ToText(-num));
}

if (num == 0)
{
return "Zero";
}

if (num <= 19)
{
var oneToNineteen = new[]
{
"One",
"Two",
"Three",
"Four",
"Five",
"Six",
"Seven",
"Eight",
"Nine",
"Ten",
"Eleven",
"Twelve",
"Thirteen",
"Fourteen",
"Fifteen",
"Sixteen",
"Seventeen",
"Eighteen",
"Nineteen"
};

return oneToNineteen[num - 1];
}

if (num <= 99)
{
result = new StringBuilder();

var multiplesOfTen = new[]
{
"Twenty",
"Thirty",
"Forty",
"Fifty",
"Sixty",
"Seventy",
"Eighty",
"Ninety"
};

result.Append(multiplesOfTen[(num / 10) - 2]);

if (num % 10 != 0)
{
result.Append(" ");
result.Append(ToText(num % 10));
}

return result.ToString();
}

if (num == 100)
{
return "One Hundred";
}

if (num <= 199)
{
return string.Format("One Hundred and {0}", ToText(num % 100));
}

if (num <= 999)
{
result = new StringBuilder((num / 100).ToText());
result.Append(" Hundred");
if (num % 100 != 0)
{
result.Append(" and ");
result.Append((num % 100).ToText());
}

return result.ToString();
}

if (num <= 999999)
{
result = new StringBuilder((num / 1000).ToText());
result.Append(" Thousand");
if (num % 1000 != 0)
{
switch ((num % 1000) < 100)
{
case true:
result.Append(" and ");
break;
case false:
result.Append(", ");
break;
}

result.Append((num % 1000).ToText());
}

return result.ToString();
}

if (num <= 999999999)
{
result = new StringBuilder((num / 1000000).ToText());
result.Append(" Million");
if (num % 1000000 != 0)
{
switch ((num % 1000000) < 100)
{
case true:
result.Append(" and ");
break;
case false:
result.Append(", ");
break;
}

result.Append((num % 1000000).ToText());
}

return result.ToString();
}

result = new StringBuilder((num / 1000000000).ToText());
result.Append(" Billion");
if (num % 1000000000 != 0)
{
switch ((num % 1000000000) < 100)
{
case true:
result.Append(" and ");
break;
case false:
result.Append(", ");
break;
}

result.Append((num % 1000000000).ToText());
}

return result.ToString();
}
`````` 2022-06-07 7 楼

There's no built in solution in `.net`, but there are good libraries around. The best currently is definitely Humanizr:

``````Console.WriteLine(794663.ToWords()); // => seven hundred and ninety-four thousand six hundred and sixty-three
``````

It also supports ordinal, and roman representations:

``````Console.WriteLine(794663.ToOrdinalWords()); // => seven hundred and ninety-four thousand six hundred and sixty third
Console.WriteLine(794.ToRoman()); // => DCCXCIV
``````

`Humanizr` also has a wide range of tools regarding `string`, `DateTime`, `TimeSpan` and so forth.

``````Console.WriteLine(794.Seconds().Humanize().Underscore().Hyphenate()); // => 13-minutes
`````` 2022-06-07 6 楼

Based on Ryan Emerle's solution, this adds dashes at the correct locations, does not include trailing spaces, does not pluralize numbers, and properly handles an input of zero (0):

``````public static string ToText(long n) {
return _toText(n, true);
}
private static string _toText(long n, bool isFirst = false) {
string result;
if(isFirst && n == 0) {
result = "Zero";
} else if(n < 0) {
result = "Negative " + _toText(-n);
} else if(n == 0) {
result = "";
} else if(n <= 9) {
result = new[] { "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine" }[n - 1] + " ";
} else if(n <= 19) {
result = new[] { "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen" }[n - 10] + (isFirst ? null : " ");
} else if(n <= 99) {
result = new[] { "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety" }[n / 10 - 2] + (n % 10 > 0 ? "-" + _toText(n % 10) : null);
} else if(n <= 999) {
result = _toText(n / 100) + "Hundred " + _toText(n % 100);
} else if(n <= 999999) {
result = _toText(n / 1000) + "Thousand " + _toText(n % 1000);
} else if(n <= 999999999) {
result = _toText(n / 1000000) + "Million " + _toText(n % 1000000);
} else {
result = _toText(n / 1000000000) + "Billion " + _toText(n % 1000000000);
}
if(isFirst) {
result = result.Trim();
}
return result;
}
`````` 2022-06-07 5 楼

This thread was a great help. I like Ryan Emerle's solution the best for its clarity. Here's my version which I think makes the structure clear as day:

``````public static class Number
{
static string[] first =
{
"Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine",
"Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen",
"Seventeen", "Eighteen", "Nineteen"
};
static string[] tens =
{
"Twenty", "Thirty", "Fourty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety",
};

/// <summary>
/// Converts the given number to an english sentence.
/// </summary>
/// <param name="n">The number to convert.</param>
/// <returns>The string representation of the number.</returns>
public static string ToSentence(int n)
{
return n == 0 ? first[n] : Step(n);
}
// traverse the number recursively
public static string Step(int n)
{
return n < 0            ? "Minus " + Step(-n):
n == 0           ? "":
n <= 19          ? first[n]:
n <= 99          ? tens[n / 10 - 2] + " " + Step(n % 10):
n <= 199         ? "One Hundred " + Step(n % 100):
n <= 999         ? Step(n / 100) + "Hundred " + Step(n % 100):
n <= 1999        ? "One Thousand " + Step(n % 1000):
n <= 999999      ? Step(n / 1000) + "Thousand " + Step(n % 1000):
n <= 1999999     ? "One Million " + Step(n % 1000000):
n <= 999999999   ? Step(n / 1000000) + "Million " + Step(n % 1000000):
n <= 1999999999  ? "One Billion " + Step(n % 1000000000):
Step(n / 1000000000) + "Billion " + Step(n % 1000000000);
}
}
`````` 2022-06-07 4 楼

Here is the modified code I used:

``````//Wrapper class for NumberToText(int n) to account for single zero parameter.
public static string ConvertToStringRepresentation(long number)
{
string result = null;

if (number == 0)
{
result = "Zero";
}
else
{
result = NumberToText(number);
}

return result;
}

//Modifications from original source:
//  Changed parameter type from int to long.
//  Changed labels to be singulars instead of plurals (Billions to Billion, Millions to Million, etc.).
private static string NumberToText(long n)
{
if (n < 0)
return "Minus " + NumberToText(-n);
else if (n == 0)
return "";
else if (n <= 19)
return new string[] {"One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight",
"Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen",
"Seventeen", "Eighteen", "Nineteen"}[n - 1] + " ";
else if (n <= 99)
return new string[] {"Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy",
"Eighty", "Ninety"}[n / 10 - 2] + " " + NumberToText(n % 10);
else if (n <= 199)
return "One Hundred " + NumberToText(n % 100);
else if (n <= 999)
return NumberToText(n / 100) + "Hundred " + NumberToText(n % 100);
else if (n <= 1999)
return "One Thousand " + NumberToText(n % 1000);
else if (n <= 999999)
return NumberToText(n / 1000) + "Thousand " + NumberToText(n % 1000);
else if (n <= 1999999)
return "One Million " + NumberToText(n % 1000000);
else if (n <= 999999999)
return NumberToText(n / 1000000) + "Million " + NumberToText(n % 1000000);
else if (n <= 1999999999)
return "One Billion " + NumberToText(n % 1000000000);
else
return NumberToText(n / 1000000000) + "Billion " + NumberToText(n % 1000000000);
}
`````` 2022-06-07 3 楼
``````public string IntToString(int number)//nobody really uses negative numbers
{
if(number == 0)
return "zero";
else
if(number == 1)
return "one";
.......
else
if(number == 2147483647)
return "two billion one hundred forty seven million four hundred eighty three thousand six hundred forty seven";
}
`````` 2022-06-07 2 楼

Ah, there may not be a class to do this, but there was a code golf question which I provided a C# example for:

Code Golf: Number to Words

However, it's not the easiest to read and it only goes up to decimal.MaxValue, so I've written a new version that will go as high as you need to.

I couldn't find any information regarding values higher than vigintillions, but if you append the values to the thou[] array, you can continue going up as far as you like. It still doesn't support fractions, but I'm thinking about adding that at some point.

``````    static string NumericStringToWords(string NumericValue)
{
if ("0" == NumericValue) return "zero";

string[] units = { "one", "two", "three", "four", "five",
"six", "seven", "eight", "nine" };

string[] teens = { "eleven", "twelve", "thirteen", "four", "fifteen",
"sixteen", "seventeen", "eighteen", "nineteen" };

string[] tens = { "ten", "twenty", "thirty", "forty", "fifty",
"sixty", "seventy", "eighty", "ninety" };

string[] thou = { "thousand", "million", "billion", "trillion",
"septillion", "octillion", "nonillion", "decillion",
"udecillion", "duodecillion", "tredecillion",
"quattuordecillion", "quindecillion", "sexdecillion",
"septendecillion", "octodecillion", "novemdecillion",
"vigintillion" };

string sign = String.Empty;
if ("-" == NumericValue.Substring(0, 1))
{
sign = "minus ";
NumericValue = NumericValue.Substring(1);
}

int maxLen = thou.Length * 3;
int actLen = NumericValue.Length;
if(actLen > maxLen)
throw new InvalidCastException(String.Format("{0} digit number specified exceeds the maximum length of {1} digits.  To evaluate this number, you must first expand the thou[] array.", actLen, maxLen));

//Make sure that the value passed in is indeed numeric... we parse the entire string
//rather than just cast to a numeric type to allow us to handle large number types passed
//in as a string.  Otherwise, we're limited to the standard data type sizes.
int n; //We don't care about n, but int.TryParse requires it
if (!NumericValue.All(c => int.TryParse(c.ToString(), out n)))
throw new InvalidCastException();

string fraction = String.Empty;
if (NumericValue.Contains("."))
{
string[] split = NumericValue.Split('.');
NumericValue = split;
fraction = split;
}

StringBuilder word = new StringBuilder();
ulong loopCount = 0;

while (0 < NumericValue.Length)
{
int startPos = Math.Max(0, NumericValue.Length - 3);
string crntBlock = NumericValue.Substring(startPos);
if (0 < crntBlock.Length)
{
//Grab the hundreds tens & units for the current block
int h = crntBlock.Length > 2 ? int.Parse(crntBlock[crntBlock.Length - 3].ToString()) : 0;
int t = crntBlock.Length > 1 ? int.Parse(crntBlock[crntBlock.Length - 2].ToString()) : 0;
int u = crntBlock.Length > 0 ? int.Parse(crntBlock[crntBlock.Length - 1].ToString()) : 0;

StringBuilder thisBlock = new StringBuilder();

if (0 < u)
thisBlock.Append(1 == t? teens[u - 1] : units[u - 1]);

if (1 != t)
{
if (1 < t && 0 < u) thisBlock.Insert(0, "-");
if (0 < t) thisBlock.Insert(0, tens[t - 1]);
}

if (0 < h)
{
if (t > 0 | u > 0) thisBlock.Insert(0, " and ");
thisBlock.Insert(0, String.Format("{0} hundred", units[h - 1]));
}

//Check to see if we've got any data left and add
//appropriate word separator ("and" or ",")
bool MoreLeft = 3 < NumericValue.Length;
if (MoreLeft && (0 == h) && (0 == loopCount))
thisBlock.Insert(0, " and ");
else if (MoreLeft)
thisBlock.Insert(0, String.Format(" {0}, ", thou[loopCount]));

word.Insert(0, thisBlock);
}

//Remove the block we just evaluated from the
//input string for the next loop
NumericValue = NumericValue.Substring(0, startPos);

loopCount++;
}
return word.Insert(0, sign).ToString();
}
``````

I tested it using Decimal.MaxValue appended to itself to generate a large number of:

seven octodecillion, nine hundred and twenty-two septendecillion, eight hundred and sixteen sexdecillion, two hundred and fifty-one quindecillion, four hundred and twenty-six quattuordecillion, four hundred and thirty-three tredecillion, seven hundred and fifty-nine duodecillion, three hundred and fifty-four udecillion, three hundred and ninety-five decillion, thirty-three nonillion, five hundred and seventy-nine octillion, two hundred and twenty-eight septillion, one hundred and sixty-two sextillion, five hundred and four quintillion, two hundred and sixty-four quadrillion, three hundred and thirty-seven trillion, five hundred and ninety-three billion, five hundred and forty-three million, nine hundred and fifty- thousand, three hundred and thirty-five 2022-06-07 1 楼

I've always been a fan of the recursive method

``````  public static string NumberToText( int n)
{
if ( n < 0 )
return "Minus " + NumberToText(-n);
else if ( n == 0 )
return "";
else if ( n <= 19 )
return new string[] {"One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight",
"Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen",
"Seventeen", "Eighteen", "Nineteen"}[n-1] + " ";
else if ( n <= 99 )
return new string[] {"Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy",
"Eighty", "Ninety"}[n / 10 - 2] + " " + NumberToText(n % 10);
else if ( n <= 199 )
return "One Hundred " + NumberToText(n % 100);
else if ( n <= 999 )
return NumberToText(n / 100) + "Hundreds " + NumberToText(n % 100);
else if ( n <= 1999 )
return "One Thousand " + NumberToText(n % 1000);
else if ( n <= 999999 )
return NumberToText(n / 1000) + "Thousands " + NumberToText(n % 1000);
else if ( n <= 1999999 )
return "One Million " + NumberToText(n % 1000000);
else if ( n <= 999999999)
return NumberToText(n / 1000000) + "Millions " + NumberToText(n % 1000000);
else if ( n <= 1999999999 )
return "One Billion " + NumberToText(n % 1000000000);
else
return NumberToText(n / 1000000000) + "Billions " + NumberToText(n % 1000000000);
}
``````

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