40 in Words
How do you write 40 in words?
The number 40 is written forty in words. As an ordinal it is fortieth, and on a check you would write Forty and 00/100.
Last updated 19 June 2026
Other ways to write it
| Cardinal | forty |
|---|---|
| Ordinal | fortieth |
| Currency | forty dollars |
| Check format | Forty and 00/100 |
How number-to-words spelling works
A cardinal number names a quantity (forty), while an ordinal names a position (fortieth). English hyphenates compound numbers from twenty-one to ninety-nine and groups digits into thousands, millions, and billions.
For house-style rules on spelling out numbers, see the Chicago Manual of Style, or read our guide to spelling numbers in words.
Facts about 40
- 40 is an even number.
- It is not a prime number.
- Digit sum: 4.
- Roman numerals: XL.
- Binary: 101000.
- Hexadecimal: 28.
| Digit | Place |
|---|---|
| 4 | tens |
| 0 | ones |
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Frequently asked questions
How do you write 40 in words?
40 in words is "forty".
How do you spell 40?
40 is spelled "forty".
How do you write 40 on a check?
On a check, write "Forty and 00/100".