How to write numbers in words.
When to write numbers in words, when to use the figure instead, and why two respected style guides give you different answers.
numerosaletras team · Updated August 31, 2026 · 11 min read
What you will learn
- ▸The two thresholds — Chicago spells out to one hundred, AP to nine.
- ▸Why English has no authority to settle the question.
- ▸The hyphen, plural and spelling rules that apply either way.
- ▸What changes when the number is on a contract rather than in prose.
- ▸The five mistakes that turn up most often.
01 · the short answer
Write numbers in words, or use the figure?
There is no single answer, and that is not evasion: English has no authority that could give one. What it has is style guides that disagree in public.
The Chicago Manual of Style writes numbers in words from zero through one hundred. The AP Stylebook spells out one through nine and switches to figures at 10. Both are followed by serious publishers, and a sentence written correctly under one looks wrong under the other.
So the practical question is not "what is correct" but "which guide am I following". If nobody has told you, pick one and be consistent — that consistency is what a reader actually notices. For the mechanics of any particular number, the number to words converter on this site handles the hyphens and the scale words for you.
02 · the two thresholds
Nine, or one hundred.
Chicago Manual of Style
Spell out zero to one hundred
Plus round numbers above it — two hundred, five thousand. Built for books, where prose reads better with the words. "There were ninety-four applicants."
AP Stylebook
Spell out one to nine
Figures from 10 up. Built for newspapers, where a column inch is expensive and figures scan faster. "There were 94 applicants."
The gap between the two is wide — everything from ten to a hundred falls in it — and it is not an accident. AP was written for a medium where space costs money and readers skim; Chicago for one where a page of figures interrupts the reading. Each guide is right about its own medium.
Most house styles are a version of one of these two, occasionally with a local amendment for a field that uses a lot of numbers. If you are writing without one, Chicago suits essays, reports and anything read start to finish; AP suits anything scanned.
03 · no academy
Why nobody can settle this.
Spanish has the Real Academia Española. When a question of usage comes up — whether an accent belongs, how a compound number is written — there is an institution whose answer settles it for the language, and dictionaries and schools follow.
English has never had that. Attempts to found one were made and went nowhere, and what filled the gap was publishing: houses wrote down their conventions, some of those manuals became widely used, and "correct English" came to mean "consistent with a recognised manual". It is a genuinely different model, and it explains why an English style question so often has two defensible answers.
The practical consequence is worth internalising: asking whether it is correct to write "94" or "ninety-four" is asking a question with no answer. Asking which one your publication uses is a question with a clear one.
04 · what both agree on
Five rules with no argument.
Once you have decided to write numbers in words, the mechanics are settled. These five are not in dispute between the guides, and they apply whichever threshold you follow.
▸ Hyphens
Twenty-one through ninety-nine take a hyphen, always. Above the hundred the hyphen stops: one hundred twenty-one, not one-hundred-twenty-one. This is the most frequent error in written amounts and the easiest to fix.
▸ Singular scale words
Hundred, thousand, million and billion stay singular after a number: two million, not two millions. The "s" belongs only to vague quantities — millions of people.
▸ Forty
Four, fourteen and fourth keep the "u"; forty drops it. There is no reasoning behind it, only the spelling, and it appears misspelled in legal documents constantly.
▸ No "and" in American usage
One hundred twenty-three. British usage inserts the conjunction — one hundred and twenty-three — and neither is an error. On a check, though, keep to one "and", because that word already separates the dollars from the cents.
▸ Start of a sentence
A sentence never opens with a figure. Either spell the number out or, if that reads awkwardly, rewrite the sentence so the number is not first. This is the one rule every style guide agrees on without qualification.
| Figure | In words | Note |
|---|---|---|
| 7 | seven | Both guides spell it out. |
| 21 | twenty-one | Hyphenated. Chicago spells it; AP uses the figure. |
| 40 | forty | No "u", unlike four and fourteen. |
| 100 | one hundred | The last number Chicago spells out by default. |
| 123 | one hundred twenty-three | American usage: no "and". |
| 1,234 | one thousand two hundred thirty-four | Figures in both guides at this size. |
| 2,000,000 | two million | Scale words never take an "s". |
| 0.5 | zero point five | Decimals are read digit by digit. |
05 · when it stops being style
On a contract, the rules change.
Everything above is about prose, where writing numbers in words is a matter of taste and consistency. On a check, a promissory note or the payment clause of a contract, it stops being taste: the amount is written both ways, and if the two disagree, the written words are what binds.
That rule is why the conventions there look fussy. The cents go over one hundred because a fraction cannot be altered; the leftover space on the line gets a stroke through it because a gap is where a word can be added; the whole amount still needs its 00/100. None of that is style — it is fraud prevention with a long history.
The check-writing guide covers the amount line field by field, and the contracts article covers the phrasing used in agreements.
06 · mistakes
Five that keep appearing.
— twenty one, thirty five
+ twenty-one, thirty-five
Every compound from twenty-one to ninety-nine is hyphenated. It is a single word, not two.
— fourty
+ forty
The most misspelled number in English, and the one most likely to appear on a contract.
— "3 people attended" at the start of a sentence
+ Three people attended
No sentence begins with a figure. If spelling it out is clumsy, recast the sentence.
— Mixing styles: "We hired 5 people and twelve contractors"
+ Pick one threshold and hold it
Within a single passage, comparable quantities should be written the same way. Switching mid-sentence reads as an accident.
— 1,5 million in an English document
+ 1.5 million
The comma is the decimal separator in much of Europe and Latin America. In English it groups thousands, and the two conventions differ by a factor of a thousand.
07 · questions
Frequently asked questions.
-
Q01
Where is the line between spelling out and using figures?
Each style guide draws it somewhere different. The Chicago Manual of Style spells out whole numbers from zero through one hundred, plus round numbers above that. The AP Stylebook spells out one through nine and uses figures from 10 up. Both are widely followed, and neither is more correct — what matters is picking one and holding it across the document.
-
Q02
Why do Chicago and AP disagree?
They were written for different readers. AP was built for newspapers, where space is tight and figures are quicker to scan, so its threshold is low. Chicago was built for books, where prose reads better with numbers written out, so its threshold is high. The disagreement is about the medium rather than about grammar.
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Q03
Is English the only language without an academy for this?
Not the only one, but the contrast with Spanish is sharp. Spanish has the Real Academia Española, whose rulings settle questions like this for the whole language. English has competing style guides that disagree openly, so "correct" in English usually means "consistent with the guide you follow".
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Q04
Do I hyphenate numbers over one hundred?
Only the compound part. One hundred twenty-one keeps the hyphen between twenty and one, and takes none between hundred and twenty. Writing one-hundred-twenty-one is a common over-correction.
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Q05
How do I write numbers in legal documents?
Differently from prose. Contracts, checks and promissory notes write the amount twice — in words and in figures — and the words prevail if the two disagree. That is a legal convention rather than a style choice, and it overrides whichever guide you otherwise follow.
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Q06
Should I write "one hundred and twenty-three"?
In British English, yes; in American English, no. Both are standard in their own place. The one context where it genuinely matters is a check, where the word "and" already separates the dollars from the cents, so a second one blurs the line.
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Q07
How do I handle a number at the start of a sentence?
Spell it out, whatever your threshold otherwise is — "Nineteen ninety-nine was the year", not "1999 was the year". If the number is long enough that spelling it out looks absurd, the accepted fix is to rewrite the sentence so it does not start there.
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Q08
What about numbers in the same sentence as one another?
Keep comparable quantities in the same form: "We hired five people and twelve contractors", not "5 people and twelve contractors". Where one of them crosses your threshold, most guides let you break the rule for consistency rather than break the parallel.
Pick a threshold and hold it.
Chicago to one hundred, AP to nine, or your employer's own line. What a reader notices is not which one you chose but whether you kept to it — and once the threshold is settled, writing numbers in words is mechanical enough to hand to a converter.