Converters
Roman Numeral Converter
Convert a number to Roman numerals or a Roman numeral back to a number, for values from 1 to 3999. Type in either box and the other updates instantly, with validation so you never get a malformed numeral.
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Frequently asked questions
What range of numbers can it convert?
1 to 3999, which is the standard range for classic Roman numerals using the letters I, V, X, L, C, D and M.
How are Roman numerals written?
Symbols are added from largest to smallest (e.g. MMXXIV = 2024), and subtractive pairs like IV (4) and IX (9) avoid four repeats of a symbol.
Does it catch invalid numerals?
Yes. Malformed numerals like “IIII” or “IC” are rejected, so you only get valid, canonical results.
Is the converter free?
Yes, completely free with no sign-up. It runs entirely in your browser.