Roman Numeral Converter
Convert a number into Roman numerals, or a Roman numeral back into a number. Both directions update instantly.
Number → Roman
Roman → Number
About Roman numerals
Roman numerals still appear on clocks, book chapters, movie credits, the Super Bowl and monument dates. This converter turns ordinary numbers into Roman numerals and back again, following the standard rules, so you can read or write them with confidence.
How to use it
- Type a number (1–3999) on the left to get its Roman numeral.
- Type a Roman numeral on the right to get the number.
- Copy whichever result you need.
Frequently asked questions
What range does it support?
Standard Roman numerals run from 1 to 3999 (I to MMMCMXCIX). There’s no zero or negative number in the Roman system.
How do Roman numerals work?
They combine the letters I (1), V (5), X (10), L (50), C (100), D (500) and M (1000). Smaller values before larger ones are subtracted, like IV (4) and IX (9).
Why is my Roman numeral marked invalid?
Check it only uses I, V, X, L, C, D, M and follows standard rules. For example IIII isn’t valid — 4 is written IV.
Is it private?
Yes, everything runs in your browser.
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