Roman numeral symbols
| I | V | X | L | C | D | M |
|---|---|---|---|---|---|---|
| 1 | 5 | 10 | 50 | 100 | 500 | 1000 |
Rules for reading and writing Roman numerals
- Symbols are written from largest to smallest and added: VIII = 5 + 3 = 8.
- A smaller symbol before a larger one is subtracted — only in six combinations: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900).
- I, X, C and M can repeat up to three times in a row; V, L and D never repeat.
Where you’ll still see Roman numerals
Clock faces, book chapters and prefaces (in lowercase), movie copyright years, names of monarchs and popes (Charles III), Super Bowl numbers, and outlines. The converter validates input strictly, so invalid forms such as IIII, VV or IC are flagged.
How to use the converter
- Type a number from 1 to 3,999 to see it in Roman numerals, or type Roman numerals (I, V, X, L, C, D, M) to convert them to a number.
- The converter shows the breakdown — which symbols make up each place value — and flags invalid combinations such as IIII or VX.
Common conversions
- 1–10: I, II, III, IV, V, VI, VII, VIII, IX, X
- Tens: X (10), XX (20), XXX (30), XL (40), L (50), LX (60), LXX (70), LXXX (80), XC (90)
- Hundreds: C (100), CC (200), CCC (300), CD (400), D (500), DC (600), DCC (700), DCCC (800), CM (900)
- Years: MCMXC (1990), MM (2000), MMX (2010), MMXX (2020), MMXXVI (2026)
Converting step by step
Split the number into thousands, hundreds, tens and ones, convert each part separately and join them. For 2,749: 2,000 = MM, 700 = DCC, 40 = XL, 9 = IX, so 2,749 = MMDCCXLIX. To read a numeral, add the values from left to right, but subtract any symbol that is smaller than the one after it.
Why there’s no zero and a 3,999 limit
The Roman system was designed for counting and recording amounts, not for written arithmetic, so it has no symbol for zero. The largest number that follows the standard rules is MMMCMXCIX (3,999), because M can be repeated at most three times. For larger numbers, medieval writers used a bar over a numeral (vinculum) to multiply it by 1,000 — V̄ = 5,000 — but this isn’t standard in modern use.
Exceptions you may see
- IIII on clocks: many clock and watch faces use IIII instead of IV for 4, a long tradition thought to give visual balance with VIII on the other side.
- Old inscriptions sometimes use additive forms like VIIII for 9 or XXXX for 40.
- Lowercase numerals (i, ii, iii, iv) are used to number book prefaces, lists and outlines.