How to Write Numbers in Words

Writing a number in words seems basic until you're staring at a cheque, unsure whether it's “twenty one” or “twenty-one,” or where the word “and” goes. There are real conventions here — and they matter, because on a legal document the words override the digits.

The building blocks

English number words are surprisingly regular once you see the pattern:

• 0–19 are unique words: zero, one, … nineteen.
• Tens have their own words: twenty, thirty, … ninety.
• Everything else is a combination of these plus hundred, thousand, million, and so on.

Hyphenate the compound tens

Numbers from 21 to 99 that aren't round tens take a hyphen: twenty-one, forty-seven, ninety-nine. This is the rule people most often get wrong. Round numbers (thirty, sixty) don't take one.

Hundreds and the “and” question

In British English, “and” goes before the final part: one hundred and five. In American English it's often dropped: one hundred five. Both are understood; just be consistent. For large numbers, group in threes: one million, two hundred thirty-four thousand, five hundred sixty-seven.

Decimals

In general writing, read the decimal point as “point” and each following digit individually: 3.14 is three point one four, not “three point fourteen.” For money, the decimals become cents instead (see below).

The cheque and invoice format

Money has its own convention. The amount is written with the currency word and cents spelled out:

$1,234.56 → One thousand two hundred thirty-four dollars and fifty-six cents

Note that dollar/cent become plural except when the value is exactly one, and the word “and” separates dollars from cents. Writing the amount in words is a fraud-prevention measure — it's much harder to alter than a digit.

When to spell numbers in prose

Style guides commonly say: spell out numbers under ten (or under 100), and always spell out a number that starts a sentence. Use digits for larger numbers, measurements, and anywhere precision matters. Pick a style guide and follow it consistently.

Do it instantly

The number to words converter spells any number correctly in plain or currency form, handling hyphens, scales and decimals for you — ideal for cheques and invoices. For other numeral systems, try the Roman numeral converter and the number base converter.