Roman Numeral Converter: Numbers to Roman & Back

Tooly · 2026-08-02 · 4 min read

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

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.

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