About this tool
This converter writes a number out in English the way you would on a check, in a legal document, or in a school assignment. Type digits, with or without commas and a decimal point, and it produces the cardinal words (one thousand two hundred thirty-four), the check-writing line (... and 56/100), a spoken currency amount in US dollars, euros, pounds sterling, or Indian rupees, and the ordinal form (twenty-first, 21st). It handles negative numbers, decimals read digit by digit, and integers up to one undecillion (10^36), using exact big-integer arithmetic so large values never lose digits. You can switch between the short scale used in the US and modern UK (billion = 10^9), the traditional British long scale (billion = 10^12), and the Indian lakh and crore system, and add the British 'and' (one hundred and five). A reverse converter turns words back into digits for proofreading.
How it works
The integer part is split into three-digit groups from the right. Each group of 0 to 999 is spelled from fixed word lists (one to nineteen, twenty to ninety, hundred) and given its scale word: thousand, million, billion, and so on up to undecillion (10^36) in the short scale. The long scale groups by six digits instead and uses thousand inside each group, so 10^9 becomes one thousand million. The Indian system takes the last three digits as hundreds, then two-digit groups named thousand, lakh (10^5), and crore (10^7), repeating crore for larger values. Decimals are read digit by digit after the word point. Check format rounds the fraction to cents and writes it as NN/100. Ordinals replace the final word using the irregular set (first, second, third, fifth, eighth, ninth, twelfth), change a trailing y to ieth (twentieth), and otherwise add th. The reverse converter accumulates unit and tens words, multiplies by hundred, and adds each completed group when it meets a scale word.
Frequently asked questions
How do I write a dollar amount in words on a check?
Write the whole dollars in words, then 'and' followed by the cents as a fraction over 100: $1,234.56 becomes 'One thousand two hundred thirty-four and 56/100'. If there are no cents write 'and 00/100' or 'and no/100'. Banks read the written line as the legal amount if it disagrees with the numerals, so choose Check-writing mode, copy the result, and draw a line through any leftover space.
Is it 'one hundred five' or 'one hundred and five'?
American style omits 'and' inside whole numbers: one hundred five, two thousand three hundred forty-five. British and Commonwealth style inserts 'and' before the final tens or units: one hundred and five, two thousand three hundred and forty-five. Both are correct in their regions; on US checks 'and' is reserved for separating dollars from cents, which is why the American form drops it elsewhere. Tick the British 'and' box to switch.
What is the difference between the short scale and the long scale?
In the short scale, used in the United States and since 1974 officially in the United Kingdom, each new -illion is a thousand times the previous one: million 10^6, billion 10^9, trillion 10^12. In the traditional long scale, still used in most of continental Europe in local languages, each -illion is a million times the previous: billion 10^12, trillion 10^18, with 10^9 called a thousand million or milliard. A US billion is therefore a British-long-scale thousand million.
How do lakh and crore work in the Indian numbering system?
Indian English groups digits as 3,2,2,2 instead of 3,3,3. One lakh is 100,000 (written 1,00,000) and one crore is 10,000,000 (1,00,00,000). So 1,234,567 is written 12,34,567 and read as twelve lakh thirty-four thousand five hundred sixty-seven. Larger values reuse crore: 100 crore is 10^9 (a short-scale billion) and one lakh crore is 10^12. Choose the Indian scale, or the INR currency, to get this form, and the reverse converter understands lakh and crore too.