40 in Roman numerals at a glance
- Roman numeral
- XL
- Lowercase
- xl
- Letters
- 2
- Parts
- XL
- Subtractive pairs
- XL
- In words
- forty
- Latin name
- quadraginta
How XL is built
Roman numerals are written one decimal place at a time, from the largest place to the smallest. Converting each digit of 40 separately and joining the pieces gives XL:
| Place | Digit | Value | Numeral |
|---|---|---|---|
| Tens | 4 | 40 | XL |
| Ones | 0 | 0 | — (zero has no symbol) |
Reading it back, left to right:
- XL = 40 (L minus X) → running total 40
The rules XL follows
- Largest to smallest. XL uses the symbols X and L (2 characters in all), and the values never increase from left to right except inside a subtractive pair.
- Subtraction. XL (40) is a subtractive pair: a smaller symbol in front of a larger one is taken away from it. Only six pairs are allowed — IV, IX, XL, XC, CD and CM — and XL uses one of them.
- No repeats. Every symbol in XL appears once in a row, which is why the numeral stays short.
Common mistakes when writing 40
- XXXX — wrong because standard numerals never repeat a symbol four times; 40 is written XL.
Where you will see XL
- Championship games. Pro football numbers its championship game with Roman numerals, starting from game I in January 1967. Game XL was played in early 2006.
- Volumes and sequels. Book volumes, conference editions, film sequels and anniversary events often carry a Roman numeral; edition XL would be the 40th.
Numbers near 40 in Roman numerals
Frequently asked questions
How do you write 40 in Roman numerals?
40 is written XL. It is a single symbol worth 40.
Is XXXX a correct way to write 40?
No. XXXX is wrong because standard numerals never repeat a symbol four times; 40 is written XL.
What is 40 in Latin?
The Latin cardinal number 40 is “quadraginta.” The Romans wrote it as XL.
What is XL plus one?
XL + I = XLI (41). Adding one can change the whole ending of a numeral, which is why it helps to convert to digits, add, and convert back.