45 in Roman numerals is XLV, built from XL + V (XL = 40, V = 5), which add up to 45. It uses subtractive notation: XL (50 - 10).
How 45 is written in Roman numerals
The number 45 is written XLV 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 XLV step by step — take the largest value that fits, write its symbol, subtract, repeat.
| Write | Value | Remaining before | Remaining after |
|---|
| XL | 40 | 45 | 5 |
| V | 5 | 5 | 0 |
Where you see XLV
The 45th Super Bowl was Super Bowl XLV; the NFL has used Roman numerals for every edition except Super Bowl 50.
Nearby numbers
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Frequently Asked Questions
What is 45 in Roman numerals?
45 in Roman numerals is XLV. Reading it left to right gives XL (40) + V (5) = 45. The number below it, 44, is written XLIV, and the number above it, 46, is written XLVI.
How do you write 45 in Roman numerals?
Write 45 as XLV, combining XL (40) + V (5). Roman numerals are built by taking the largest value that still fits, writing its symbol and subtracting it, which reduces 45 in 2 steps: XL leaves 5, V leaves 0. Every symbol keeps the same value wherever it stands, so the order is fixed and XLV is the only standard spelling of 45.
Does XLV use subtractive notation?
Yes, XLV uses subtractive notation. Here XL means 50 minus 10. Without it, 45 would have to be written XXXXV, and Roman numerals avoid a run of four identical letters wherever a subtractive pair will do.
What is 45 times ten in Roman numerals?
45 times ten is 450, which is CDL in Roman numerals, not XLV 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 XLV for 45 with CDL for 450.