Roman Numeral Converter
Convert any number from 1 to 3999 into Roman numerals — and Roman numerals back into numbers.
Symbols: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. A smaller symbol before a larger one subtracts: IV=4, IX=9, XL=40, CM=900.
About this tool
Roman numerals still show up on clock faces, book chapters, film copyright dates (MMXXVI = 2026), monuments and the Super Bowl. The system is additive with a subtractive twist: symbols add up, except when a smaller symbol sits immediately before a larger one, when it subtracts instead.
The classical system has no zero and tops out at 3999 (MMMCMXCIX) — beyond that, medieval scribes added bars and brackets, which this converter deliberately does not guess at. Invalid forms like IIII or VV are flagged rather than silently accepted.
How to use it
- Type a number to see its Roman numeral, or type a numeral to see its number.
- Both directions update as you type.
Frequently asked questions
Why does the converter stop at 3999?
Standard Roman numerals have no symbol larger than M (1000) and never repeat a symbol more than three times, so 3999 (MMMCMXCIX) is the largest standard value.
Is IIII a valid Roman numeral?
Not in the standard rules — 4 is IV. IIII survives on some traditional clock faces, but as a numeral it is non-standard, and this converter flags it.
What year is MMXXVI?
MMXXVI = 2026: MM (2000) + XX (20) + VI (6).