Roman Numeral Converter: Numbers ⇄ Roman Numerals (Free)
Roman numerals show up more than you'd expect — movie copyright years, book chapters, clock faces, Super Bowls, monarch and pope names, building cornerstones. Reading or writing them correctly past a few digits takes a moment of thought. A converter does it both ways instantly. Here's how to use one, plus a quick explainer of how the system works.
How Roman numerals work
Seven letters, each a value:
I= 1,V= 5,X= 10,L= 50,C= 100,D= 500,M= 1000.
You add them left to right (XV = 15), with one twist: when a smaller value precedes a larger one, you subtract it. So IV = 4 (5 − 1), IX = 9, XL = 40, CM = 900. That subtractive rule is where mistakes happen — and why MCMXCIV (1994) takes a second to decode.
The standard system covers 1 to 3999 (there's no single symbol for zero or for values above a few thousand without extensions).
How to use the converter
The free Roman Numeral converter:
- Open it — no signup.
- Enter a number to get the Roman numeral, or a Roman numeral to get the number.
- Copy the result.
It runs in your browser, instantly, with nothing uploaded.
Where you'll use it
- Decoding copyright years — figuring out that
MMXXIVis 2024. - Naming and numbering — chapters, sequels, monarchs, events.
- Clocks, cornerstones, monuments — reading dates inscribed in numerals.
- Design — adding a classical touch to a layout or title.
- Homework and learning — checking conversions both ways.
Common questions
What range do Roman numerals cover? The standard system runs 1 to 3999.
Why is 4 written IV and not IIII? The subtractive rule: a smaller numeral before a larger one is subtracted, so IV = 5 − 1 = 4. (Clock faces sometimes use IIII by tradition, but IV is standard.)
Is my input private? Yes — the converter runs in your browser and uploads nothing.
Related reading: Number to Words · explore the other free tools.
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