Convert any number to Roman numerals or decode Roman numerals back to numbers — instantly.
| Symbol | Value | Notes |
|---|---|---|
| I | 1 | Can be placed before V and X to subtract |
| V | 5 | Cannot be repeated |
| X | 10 | Can be placed before L and C to subtract |
| L | 50 | Cannot be repeated |
| C | 100 | Can be placed before D and M to subtract |
| D | 500 | Cannot be repeated |
| M | 1,000 | Can be repeated up to 3 times (MMM = 3000) |
Roman numerals use seven symbols: I, V, X, L, C, D, and M. Numbers are formed by combining symbols, generally from largest to smallest from left to right. When a smaller symbol appears before a larger one, it is subtracted rather than added — for example, IV = 4 (5 minus 1) and IX = 9 (10 minus 1).
Standard Roman numerals can represent numbers from 1 to 3,999. The system was widely used throughout the Roman Empire and is still used today for clock faces, movie sequels, Super Bowl numbering, and copyright dates.