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Roman Numeral Converter: Numbers to Roman & Back
Roman numerals show up in history class, movie credits, clock faces, and even API version numbers. A Roman numeral converter translates numbers to Roman and back instantly — no mental gymnastics with IV, XL, and CM. No signup, nothing uploaded.
How Roman numerals work
- I=1, V=5, X=10, L=50, C=100, D=500, M=1000
- Subtractive rule: IV=4, IX=9, XL=40, XC=90, CM=900
- Everything else is additive: MCMXCIV = 1994
Convert Roman numerals free with Tooly
The Tooly Roman Numeral Converter handles both directions:
- Type a number → get the Roman numeral instantly
- Paste Roman numerals → get the number
- Handles the full standard range correctly
- 100% client-side — nothing is uploaded
Convert Roman numerals free — no signup
Open Roman Numeral Converter
Open Roman Numeral Converter
Quick reference
| Number | Roman |
|---|---|
| 4 | IV |
| 9 | IX |
| 40 | XL |
| 99 | XCIX |
| 500 | D |
| 1994 | MCMXCIV |
When you'll use it
- History and Latin class homework
- Decoding movie release years (MMXXIV, anyone?)
- Reading clock faces and building plaques/signs
- Understanding software version numbers (e.g., iOS 18, macOS Sequoia)
Frequently Asked Questions
Is this Roman numeral converter really free? Yes — unlimited conversions, no account, no watermark.
Does it handle large numbers? Standard numerals up to thousands convert correctly; beyond that, the classic system breaks down (the Romans had no zero!).
Is my input uploaded? No — conversion runs entirely in your browser.
What else should I check? The Number to Words and Percentage Calculator tools cover the rest of your number needs.