Number to Words Converter: Write Figures in English Free
Convert any figure into Spanish words: ideal for invoices, checks, contracts and legal documents. Supports decimals and currency.
Convert any number to Spanish words following RAE rules: checks, invoices, contracts and official documents. Includes examples and validation.
By VOV · Last updated: October 21, 2026
Examples
Use cases
- Write out the amount in words on a Mexican check so the bank accepts it without any rejections
- Write the amount in words in your lease contract, as the required legal formality demands
- Spell the figures out as words on your electronic invoice to meet the SAT requirements
Frequently asked questions
How are numbers written in words per the RAE?
From 0 to 29 they are written as a single word (dieciséis, veintidós); from 31 on they are separated (treinta y uno). 100 alone is "cien", "ciento" when followed; 500, 700 and 900 are quinientos, setecientos and novecientos.
What is converting numbers to words for?
It is required on electronic invoices, checks, promissory notes and contracts in Mexico, Colombia and Spain as an anti-fraud measure: the written amount prevails over the figure.
What range of numbers is supported?
From 0 to 999 billion, with up to two decimals. Decimals are expressed as a fraction (e.g. "con 56/100").