Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers.
Roman numerals survive in movie credits, clock faces, book chapters, Super Bowl numbering, and monument inscriptions — which means every so often you need to decode MCMXCIV (1994) or write 2026 as MMXXVI. The subtractive rules (IV for 4, XC for 90) make hand conversion easy to get subtly wrong.
This converter works in both directions: type a number from 1 to 3999 to get its Roman numeral, or paste a numeral to get the number back. It validates strictly, rejecting malformed forms like IIII or VX, so you can also use it to check whether an inscription or tattoo draft is actually correct.
How to use Roman Numeral Converter
- 1
Choose a direction
Number → Roman, or Roman → number.
- 2
Type the value
A number from 1–3999, or a numeral using I, V, X, L, C, D, M.
- 3
Copy the result
The conversion appears instantly with validation errors explained.
Features
- Bidirectional conversion with strict validation
- Rejects malformed numerals instead of guessing
- Covers the full classical range 1–3999
Frequently asked questions
Common mistakes to avoid
- Writing 999 as IM — subtraction only works with I, X and C before the next two larger symbols (999 is CMXCIX).
- Repeating V, L or D — these symbols can appear at most once in a valid numeral.
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