Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers, from I to MMMCMXCIX (1–3999), with the subtractive rules explained.
MMXXVI
2,026
Symbol values
| Symbol | Value | Subtractive pair |
|---|---|---|
| I | 1 | IV = 4, IX = 9 |
| V | 5 | — |
| X | 10 | XL = 40, XC = 90 |
| L | 50 | — |
| C | 100 | CD = 400, CM = 900 |
| D | 500 | — |
| M | 1,000 | — |
How Roman numerals work
Roman numerals are additive: symbols are written from largest to smallest and summed, so MMXXVI = 1000 + 1000 + 10 + 10 + 5 + 1 = 2026. The one exception is the subtractive rule: I, X and C may be placed before the next two larger symbols to subtract, giving IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). V, L and D are never repeated and never subtracted.
Standard notation has no zero and no symbol above M, so the practical range is 1 to 3999 (MMMCMXCIX). This converter validates by round-tripping: a numeral is only accepted if re-encoding the parsed value reproduces exactly what you typed, which rejects forms such as IIII or IC.
Cite this page
UnitConvertLab. (2026). Roman Numeral Converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/ar/tools/roman-numeral-converter