XL is a single Roman symbol group for 40. It uses subtractive notation: XL (50 - 10).
How 40 is written in Roman numerals
The number 40 is written XL in Roman numerals. Roman numerals use seven letters — I (1), V (5), X (10), L (50), C (100), D (500) and M (1000) — combined from largest to smallest, with subtractive pairs such as IV (4) and IX (9). Need another number? Use the Roman numeral converter or see the 1–100 chart.
Building XL step by step — take the largest value that fits, write its symbol, subtract, repeat.
| Write | Value | Remaining before | Remaining after |
|---|
| XL | 40 | 40 | 0 |
Where you see XL
The 40th Super Bowl was Super Bowl XL; the NFL has used Roman numerals for every edition except Super Bowl 50.
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Frequently Asked Questions
What is 40 in Roman numerals?
40 in Roman numerals is XL. It is written as one value group, XL, worth 40 on its own, so nothing has to be added to it. The number below it, 39, is written XXXIX, and the number above it, 41, is written XLI.
How do you write 40 in Roman numerals?
Write 40 as XL, a single Roman symbol group worth 40. Roman numerals are built by taking the largest value that still fits, writing its symbol and subtracting it, which reduces 40 in 1 step: XL leaves 0. Every symbol keeps the same value wherever it stands, so the order is fixed and XL is the only standard spelling of 40.
Why is 40 written XL rather than XXXX?
40 is written XL because Roman numerals subtract a smaller symbol placed in front of a larger one. Here XL means 50 minus 10. Spelling 40 out additively would give XXXX, 4 letters against 2, which is why the subtractive form is the standard one.
How is XL read out loud?
XL is read as the number it stands for, forty, and never letter by letter. Roman numerals are a way of writing values rather than a separate set of names, so the spoken form is the same whether the page shows 40 or XL. A chapter or volume numbered XL, for instance, is simply chapter forty.