Writing Numbers Out in Words: The Rules That Catch People

Most of the time nobody cares how you write a number. Then you hit a cheque, a contract or a legal form, and suddenly the words are the version that counts and the digits are just a cross-check.

The three-digit block method

Take 1,234,567. Break it at the commas: 1 / 234 / 567. Name each block and add its scale word. One million, two hundred thirty-four thousand, five hundred sixty-seven. That is the American form. The British form is one million, two hundred and thirty-four thousand, five hundred and sixty-seven.

The method scales without any new rules. 45,090,003 becomes 45 / 090 / 003, which reads as forty-five million, ninety thousand, three. Note that you say nothing at all for an empty hundreds column. It is ninety thousand, not zero hundred and ninety thousand.

Hyphens, commas and the word "and"

Hyphens go inside compound numbers from twenty-one through ninety-nine, so sixty-four, eighty-seven, thirty-two. They do not go between the hundred and what follows: it is two hundred sixty-four, not two-hundred-sixty-four. Commas separate the scale blocks and are optional in running prose but standard on documents. The word "and" in British usage marks the point where the last two digits arrive, which is why one hundred and one is British and one hundred one is American. Neither is wrong, but pick one and stay with it inside a single document. It is the same split that runs through US and UK measurement conventions generally.

Cheques and contracts, where it actually matters

On a US cheque, $1,250.75 is written as "One thousand two hundred fifty and 75/100 dollars". The cents go as a fraction over 100 rather than as words, and a line drawn to the end of the field stops anyone adding to it. On a UK cheque, the same amount in sterling is written as "One thousand two hundred and fifty pounds and seventy-five pence", followed by "only" if you want to close the line off.

Contracts use a belt-and-braces form: "the sum of forty-two thousand five hundred pounds (£42,500)". If the words and the figures disagree, the words are usually treated as controlling, which is precisely why the words are there. That makes it worth checking them character by character rather than trusting a glance.

Using the converter and reading its output

Type the figure into the number field using digits only. Commas are usually accepted and stripped, but currency symbols and stray spaces are the two things most likely to make it refuse. If there is a regional or style setting, pick it before you copy the result, because that switch is what controls whether "and" appears. Then check the output against your original digit by digit, working right to left, since transposed digits in the middle of a long number are the classic error and they read perfectly well in words.

Decimals, pence and cents

A converter will normally give you 0.45 as "zero point four five", reading the digits individually rather than as forty-five hundredths. For money that is not what you want, so switch to currency mode if there is one, or write the fractional part yourself. Ordinals are another setting: 21 becomes twenty-first rather than twenty-one, and the converter will only produce that if you ask for it. Numbers in other notations follow their own rules entirely, as anyone who has worked through Roman numerals already knows.

Common questions

Do I write "one hundred and one" or "one hundred one"? British English uses "one hundred and one". American English uses "one hundred one". Both are correct in their own market. On a document read in both, the version with "and" is more widely understood, and no bank has ever bounced a cheque over it.

How do I write cents on a cheque? As a fraction: "and 75/100". If the amount is a round number, write "and 00/100" rather than leaving it blank, because a blank invites additions.

Should large numbers be hyphenated throughout? No. Only the two-word numbers from twenty-one to ninety-nine take a hyphen. "Three hundred forty-seven thousand" has exactly one hyphen in it.

What about the number zero on its own? Write "zero" in American usage. British usage allows "zero" or "nought" depending on context. On a cheque you would not write it at all, since a cheque for nothing is not a cheque.