Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers (1–3,999), with validation of properly formed numerals.
How to use
- 1Type a number (1–3999) or a Roman numeral like MMXXVI.
- 2The direction is detected automatically.
How it's calculated
Symbols I 1, V 5, X 10, L 50, C 100, D 500, M 1000; a smaller symbol before a larger one is subtracted (IV = 4, XC = 90, CM = 900).
Frequently asked questions
Why do Roman numerals stop at 3,999?
Standard numerals don't repeat a symbol more than three times, and 4,000 would need MMMM or an overline notation for thousands.
Is IIII ever correct?
Clock faces traditionally use IIII for 4, but standard notation is IV.
How do I write years?
Break the year into thousands, hundreds, tens and units: 2026 = MM + XX + VI = MMXXVI.