Roman Numeral Converter
Type a number to get its Roman numeral, or paste a Roman numeral to decode it — with strict validation, for values 1 to 3999.
How Roman numerals work
Seven letters carry the values I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Letters add up left to right, except when a smaller letter sits before a larger one — then it subtracts: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900.
Quick reference
| Number | Roman | Number | Roman |
|---|---|---|---|
| 4 | IV | 90 | XC |
| 9 | IX | 400 | CD |
| 14 | XIV | 1990 | MCMXC |
| 40 | XL | 2026 | MMXXVI |
| 49 | XLIX | 3999 | MMMCMXCIX |
Frequently asked questions
Why only up to 3999?
Standard Roman numerals never repeat a letter more than three times, so 4000 would need a fourth M. The Romans wrote larger numbers with an overline (V̄ = 5000), which isn't used in modern contexts like clock faces, book chapters and movie sequels.
Is IIII ever correct for 4?
Only on clock faces, where IIII is a long-standing tradition for visual balance. Everywhere else the subtractive form IV is standard — and this converter enforces the standard form.
Is there a zero in Roman numerals?
No — the system predates the concept of zero as a numeral. Medieval scribes sometimes wrote nulla (Latin for "none") instead.
Last updated: 2026-07-13