About the Roman Numeral Converter
Convert any whole number from 1 to 3999 into its Roman numeral, or type a numeral like MCMXCIV and get 1994 back instantly. The converter applies the standard subtractive rules — IV for 4, IX for 9, XL for 40 and so on — so the output always matches the form you'll find on clock faces, monuments, book chapters, outlines and the copyright dates in film credits.
Going the other way, validation catches numerals that don't follow the rules: IIII, VX or IC are flagged rather than silently guessed, which makes the tool reliable for checking homework, decoding a movie's release year from its credits, or dating an inscription on a building. Conversion happens the moment you type, runs entirely in your browser, and is free with no account and no usage limits to worry about.
Features
- Numbers to Roman numerals and back again
- Covers the full standard range, 1 to 3999
- Validates numerals and flags malformed input
- Applies correct subtractive notation like IV and XC
- Instant conversion as you type
- Free, no sign-up, converts in your browser
How to convert Roman numerals online
- Choose the direction: number to numeral, or numeral to number.
- Enter a number from 1 to 3999, or type a Roman numeral.
- Read the converted result instantly.
- Fix any validation warning if the numeral breaks the rules.
- Copy the answer wherever you need it.
Frequently asked questions
Why is the maximum 3999?
Standard Roman notation has no symbol above M (1,000), and convention allows at most three identical symbols in a row — so 4,000 would need MMMM, which breaks the rule. Romans wrote larger values with a bar over letters (a vinculum) multiplying them by 1,000, but that notation isn't used in everyday contexts.
How does subtractive notation work?
When a smaller symbol precedes a larger one, it's subtracted instead of added: IV is 4, IX is 9, XL is 40, XC is 90, CD is 400 and CM is 900. Only those six pairings are valid — you can't write IC for 99, which must be XCIX instead.
Is IIII ever correct for 4?
You'll see IIII on many clock and watch faces — a centuries-old horological tradition, possibly kept for visual balance opposite VIII. Outside clock dials, standard modern usage is IV, and that's what this converter produces; it flags IIII as non-standard if you try to decode it.
What is zero in Roman numerals?
There isn't one. The Roman system was built for counting and recording quantities, and it simply has no symbol for zero — medieval scribes occasionally wrote the word 'nulla' instead. That's why this converter starts at 1; zero and negative numbers have no valid Roman representation.
How do I read a year like MCMXCIV?
Break it into groups: M is 1,000; CM is 900; XC is 90; IV is 4 — totalling 1994. Scan left to right, and whenever a smaller symbol sits before a larger one, subtract it. Or skip the mental arithmetic entirely: paste the numeral here and get the number instantly.