Number to Words Converter

How numbers are spelled out

This tool converts a number into written words following standard Spanish (RAE) or English rules — the format used on checks and legal documents. In Spanish, 'uno' shortens to 'un' before a noun (veintiún, treinta y un), 100 is 'cien' alone but 'ciento' in 101-199, and 'y' only appears between tens and units, never after hundreds. Add a currency to append the amount format used on real checks (e.g. pesos with 00/100 M.N. for Mexico).

How do I convert a number to words?

To convert a number to words, break it into groups of hundreds, tens and units from the largest place value down, spell each group using standard number names, and join the groups with 'thousand' or 'million' where needed. Example: 1,234 becomes 'one thousand two hundred thirty-four' (or, in Spanish, 'mil doscientos treinta y cuatro').

Steps to spell out a number

1. Split the number into millions, thousands, and the remaining hundreds group.
2. Convert each three-digit group to words using standard unit, teen and tens names.
3. In Spanish, apply the apocope rule: 'uno' shortens to 'un' and 'veintiuno' to 'veintiún' whenever it precedes a noun (as on a check).
4. Join the groups with 'mil'/'thousand' and 'millón(es)'/'million(s)' as needed.
5. If a currency is selected, append the currency name and the cents as a fraction (e.g. '34/100').

Spelling rules used

• cien = exactly 100 alone; ciento = the hundreds prefix for 101-199 (ciento uno, ciento dieciséis)
• y (and) = appears only between the tens and units digit of the same group (treinta y cuatro), never after a hundreds word
• apocope = 'un' instead of 'uno', 'veintiún' instead of 'veintiuno', used before a noun such as a currency name

Example conversions (Spanish)

Frequently asked questions

Why does this tool write 21 as 'veintiún' instead of 'veintiuno'?

This tool always spells numbers as if they precede a noun — the way they appear on a check ('veintiún pesos') or in a contract clause. That shortened form (apocope) is standard RAE usage before a noun; a number said completely on its own, with nothing following it, would use 'veintiuno' instead.

What is the difference between 'cien' and 'ciento'?

'Cien' is used only for exactly 100 by itself or before 'mil'/'millones'. Any number from 101 to 199 uses 'ciento' as a prefix, as in 'ciento dieciséis' (116).

How do I get the Mexican check format with M.N.?

Select MXN from the currency dropdown. The tool appends 'pesos', the cents as a fraction out of 100, and the 'M.N.' (Moneda Nacional) suffix used on Mexican checks.

What is the largest number this tool supports?

Up to 999,999,999 (just under one thousand million), which keeps the output within standard short-form number names without needing 'billón' or long-scale terms that vary by country.

This tool follows standard RAE spelling conventions for Spanish and standard American usage for English; some countries and institutions use slightly different check-writing conventions (e.g., 'con' instead of a slash for cents). Confirm your bank's or notary's exact required format before using this text on an official document.