42 in Roman numerals is XLII, built from XL + II (XL = 40, II = 2), which add up to 42. It uses subtractive notation: XL (50 - 10).
How 42 is written in Roman numerals
The number 42 is written XLII 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 XLII step by step — take the largest value that fits, write its symbol, subtract, repeat.
| Write | Value | Remaining before | Remaining after |
|---|
| XL | 40 | 42 | 2 |
| I | 1 | 2 | 1 |
| I | 1 | 1 | 0 |
Where you see XLII
The 42nd Super Bowl was Super Bowl XLII; the NFL has used Roman numerals for every edition except Super Bowl 50.
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Frequently Asked Questions
What is 42 in Roman numerals?
42 in Roman numerals is XLII. Reading it left to right gives XL (40) + I (1) + I (1) = 42. The number below it, 41, is written XLI, and the number above it, 43, is written XLIII.
How do you write 42 in Roman numerals?
Write 42 as XLII, combining XL (40) + I (1) + I (1). Roman numerals are built by taking the largest value that still fits, writing its symbol and subtracting it, which reduces 42 in 3 steps: XL leaves 2, I leaves 1, I leaves 0. Every symbol keeps the same value wherever it stands, so the order is fixed and XLII is the only standard spelling of 42.
Why is 42 written XLII rather than XXXXII?
42 is written XLII because Roman numerals subtract a smaller symbol placed in front of a larger one. Here XL means 50 minus 10. Spelling 42 out additively would give XXXXII, 6 letters against 4, which is why the subtractive form is the standard one.
What is 42 times ten in Roman numerals?
42 times ten is 420, which is CDXX in Roman numerals, not XLII with a letter added on the end. Roman numerals have no place value, so multiplying by ten respells the whole numeral instead of shifting digits along. Compare XLII for 42 with CDXX for 420.