This tool spells any number into its French word form (nombres en lettres) — useful for cheques, contracts and learning. It applies the famously tricky French rules automatically and runs entirely in your browser.
How it works
The converter spells each three-digit group and applies metropolitan French conventions:
- 70-79 use soixante-dix (60 + 10..19), and 80-99 use quatre-vingts (4 × 20).
- quatre-vingts keeps its plural -s only when it ends the number — quatre-vingts but quatre-vingt-un.
- The connector et joins a trailing 1 or 11 to a ten (vingt-et-un, soixante-et-onze).
- cent takes an -s when multiplied and final (deux cents) but loses it before another number (deux cent un); mille is invariable.
Example
| Number | French |
|---|---|
| 71 | soixante-et-onze |
| 80 | quatre-vingts |
| 81 | quatre-vingt-un |
| 200 | deux cents |
| 201 | deux cent un |
So 1234 spells out as mille deux cent trente-quatre.
All processing is 100% client-side — your numbers never leave your browser.
Why French number spelling is genuinely difficult
French numbers are unusual among European languages because the tens system does not use unique words for 70, 80, and 90. Instead, French builds these from arithmetic — a system inherited from an older vigesimal (base-20) counting tradition. This makes numbers in the 60s–90s particularly error-prone for learners and non-native writers.
The vigesimal section: 60–99
| Range | Pattern | Example |
|---|---|---|
| 60–69 | soixante + unit | 63 = soixante-trois |
| 70–79 | soixante-dix + (10–19) | 71 = soixante-et-onze, 75 = soixante-quinze |
| 80–89 | quatre-vingts + unit | 80 = quatre-vingts, 83 = quatre-vingt-trois |
| 90–99 | quatre-vingt-dix + (10–19) | 91 = quatre-vingt-onze, 97 = quatre-vingt-dix-sept |
The key rule: soixante-dix (70) means “sixty-ten”; quatre-vingts (80) means “four-twenties”; quatre-vingt-dix (90) means “four-twenties-ten.” These are not typos or archaic forms — they are the current standard in France today.
When et appears — and when it does not
The connector et (meaning “and”) joins a ten to a trailing 1 or 11, but only in specific positions:
- vingt et un (21), trente et un (31), quarante et un (41), cinquante et un (51), soixante et un (61), soixante et onze (71)
- Not used: quatre-vingt-un (81) — no et; quatre-vingt-onze (91) — no et
The rule stops at 80 because quatre-vingts already contains the word vingts, making the et construction grammatically awkward. The converter applies these rules automatically.
The plural -s on cents and vingts
Two words take an optional plural -s that disappears when followed by another number:
- cent: deux cents (200) but deux cent un (201), deux cent cinquante (250)
- vingts in quatre-vingts: quatre-vingts (80) but quatre-vingt-un (81), quatre-vingt-dix (90)
The -s signals “a complete unit of 100 or 20” — once another digit follows, the unit is no longer complete and the plural drops.
Mille is invariable
Unlike English “thousands,” mille never takes a plural -s regardless of quantity: deux mille (2,000), dix mille (10,000). This is one of the simpler French rules, but easy to get wrong by analogy with English.
Metropolitan French vs. Belgian and Swiss variants
This converter uses metropolitan French (France standard):
- 70 = soixante-dix
- 80 = quatre-vingts
- 90 = quatre-vingt-dix
Belgian French and Swiss French use different words: septante (70), huitante or octante (80), nonante (90). These regional forms are widely understood but are not the standard taught in French schools or used on official documents in France. If you need Belgian or Swiss French spelling, the output of this converter will be understood but may look non-standard to a local reader.
When you actually need this: practical use cases
- Cheques and bank transfers: French cheques require the amount written in words (nombres en lettres). Banks use this to resolve disputes between the numeric and written amounts.
- Legal contracts and notarial deeds: French contract law often requires sums to be expressed in words. A notaire will use this spelling on property deeds and other official instruments.
- Language learning and translation: the unusual 70–99 system is a classic stumbling block. Spelling out numbers in the tool and reading the result is an effective way to drill these forms.
- Accounting and official filings: VAT declarations and certain French tax forms require amounts written in full.
Always verify the result against the numeric figure before using on an official document — spelling a large sum incorrectly on a legal instrument can create ambiguity.