The most powerful, accurate and robust number conversion tool developed in C# for .NET Framework 4.5 and higher.

• Handles both positive and negative numbers.
• Handles a high range of numbers ranging from -1 to 1 Octillion; That is (+/-) 1,000,000,000,000,000,000,000,000,000.
• Handles numbers with decimal places. e.g; 1,234.567 = One thousand, two hundred and thirty four point five six seven
• Accurately uses commas & the and conjunction when converting large numbers to output a very grammatically correct sentence. e.g; 12,654,768,123 = Twelve billion, Six hundred and fifty four million, seven hundred and sixty eight million, one hundred and twenty three.
• Fast and efficient conversions with speeds of less than 1 microsecronds.

using System;

namespace NumberConverter.Examples
{
    class Program
    {
        static void Main(string[] args)
        {
            NumberConverter numberConverter = new NumberConverter();

            string numberInWords = numberConverter.ConvertToWords("12,345.89");

            // Or (The method has been overloaded to handle both strings and numerical values)

            numberInWords = numberConverter.ConvertToWords(12345.89);

            Console.WriteLine(numberInWords);
            Console.ReadKey();
        }
    }
}

Output: Twelve thousand, three hundred and forty five point eight nine

Numbers greater than 999,999,999,999,999 - Nine hundred and ninety nine trillion, nine hundred and ninety nine billion, nine hundred and ninety nine million, nine hundred and ninety nine thousand, nine hundred and ninety nine should be passed as a string for accurate coversion.

i.e;

numberInWords = numberConverter.ConvertToWords("1,000,000,000,000,001"); //Will be One quadrillion and one. but
numberInWords = numberConverter.ConvertToWords(1000000000000001); //Will be Over one quadrillion.

• Dennis Kay - C# Enthusiast - GitHub