Roman Numeral Converter
Type a number to get its Roman numeral, or type a numeral to get the number — both directions update live.
How to use it
- Type a number or a numeral Enter a number from 1 to 3999, or a Roman numeral like MMXXIV.
- Read the conversion The other field updates instantly.
Examples
| 4 | IV |
|---|---|
| 2024 | MMXXIV |
| 3999 | MMMCMXCIX |
About this tool
Roman numerals still appear on clocks, in book chapters, film credits and event names. This converter translates in both directions and validates its input, so a malformed numeral like “IIII” or “IC” is rejected rather than silently misread.
It covers the standard range of 1 to 3999 and runs entirely in your browser.
Frequently asked questions
Why is the range limited to 3999?
Standard Roman numerals use M for 1000 and have no single symbol for higher values, so 3999 (MMMCMXCIX) is the largest commonly written number.
How does subtractive notation work?
A smaller symbol before a larger one means subtraction, so IV is 4 and IX is 9, rather than IIII or VIIII.
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Updated June 12, 2026