Roman numeral symbols
| Symbol | Value | Symbol | Value |
|---|---|---|---|
| I | 1 | C | 100 |
| V | 5 | D | 500 |
| X | 10 | M | 1,000 |
| L | 50 |
Lower-case numerals (i, ii, iii, iv) mean the same and are common for page numbers in a book's front matter; this converter accepts either case. There is no symbol for zero, and the standard system stops at 3999 (MMMCMXCIX), because M can be written at most three times.
The rules
- Add from largest to smallest. Symbols are written in decreasing order and added: VIII = 5 + 1 + 1 + 1 = 8.
- No more than three in a row. I, X, C and M can repeat up to three times. Four of the same is wrong: 4 is IV, not IIII.
- V, L and D never repeat, because VV would just be X.
- Subtract with six pairs only. A smaller symbol before a larger one is subtracted, but only in IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). I can only come before V and X, X before L and C, and C before D and M. So 99 is XCIX, not IC, and 5 can't be written VX.
- One subtraction at a time. 8 is VIII, not IIX.
Every valid numeral has exactly one correct spelling, which is why the converter can check your input strictly. Clock faces sometimes show 4 as IIII. That's a long-standing design tradition, but this converter follows the standard rules, so it rejects IIII and tells you why.
How to convert a number
Split the number into thousands, hundreds, tens and units, and write each part separately:
To read a numeral, go left to right: add each symbol, unless it's smaller than the one after it, in which case subtract it. MCMXCIV = 1000 − 100 + 1000 − 10 + 100 − 1 + 5 = 1994.
Years in Roman numerals
| Year | Roman numeral | Breakdown |
|---|---|---|
| 1999 | MCMXCIX | M + CM + XC + IX |
| 2000 | MM | M + M |
| 2010 | MMX | M + M + X |
| 2024 | MMXXIV | M + M + X + X + IV |
| 2025 | MMXXV | M + M + X + X + V |
| 2026 | MMXXVI | M + M + X + X + V + I |
Roman numerals still appear on clock faces, book chapters and prefaces, film copyright dates, the names of monarchs and popes, major sporting events and outlines. They're also popular for dates in tattoos and engravings: write each part separately, so 15 August 2026 is XV · VIII · MMXXVI. Check the numeral here before it goes anywhere permanent. For other number formats, try the unit converter or the scientific calculator.
Frequently asked questions
What is 2026 in Roman numerals?
Why is 4 written IV and not IIII?
Why is IC not 99?
What is the largest Roman numeral?
Is there a Roman numeral for zero?
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