Roman Numeral Converter — Both Directions
MCMXCIV one way, 1994 the other, a whole list at a time.
Runs on your device What you paste is processed by your own browser. It is never sent to a server, and it is not stored anywhere after you leave the page.
Short answer
Roman numerals can be converted for free in a web browser in either direction: a whole number from 1 to 3999 comes back as a numeral, and a numeral comes back as a number. The direction is read from each line, so a mixed list converts in one pass. Only well-formed numerals are accepted — IIII, VX and IC are refused rather than guessed at — and the output uses the standard subtractive form, so 1994 is MCMXCIV rather than MDCCCCLXXXXIIII.
At a glance
| Accepts | One number from 1 to 3999, or one numeral, per line |
|---|---|
| Produces | Each line converted to the other form |
| Processing | In your browser |
| Price | Free, no limits |
| Account | Not required |
There is no direction to choose here, because every line already says which way it is going: MMXXV is a numeral and 2025 is not. A mixed list — a date off a building, a chapter number, a copyright line at the end of a film — converts in one pass.
Malformed numerals are refused on purpose. IIII looks like four and IC looks like ninety-nine, but neither is a Roman numeral, and a converter that quietly accepted them would be putting a number in front of you that the numeral does not say. The range stops at 3999 for the same reason: above MMMCMXCIX the classical system needs an overline to multiply by a thousand, and an overline does not survive plain text.
How to use it
- 1
Type numbers or numerals
One per line. Either form, in any mixture — 1994, MMXXV, 42, XIV.
- 2
Convert
Each line comes back as the other form, with the original kept next to it.
- 3
Check the form
A numeral that is not well formed is reported rather than converted, which is how a transcription error shows up.
- 4
Copy the result
Copy to the clipboard, or download it as a text file.
Frequently asked questions
What is the largest Roman numeral?
MMMCMXCIX, which is 3999. Larger values were written with a bar over the numeral to multiply it by a thousand — a notation plain text cannot carry, so this page stops there.
Is there a Roman numeral for zero?
No. The system has no zero and no negative numbers. It was built for counting and labelling, where there was never anything to name with a symbol for nothing.
Why is IIII rejected when clock faces use it?
Because a clock face is a deliberate exception, chosen so that IIII balances VIII across the dial. In writing, four is IV, and that is the only form this page produces or accepts.
Can it convert a year?
Yes — any whole number from 1 to 3999, which covers every year a Roman numeral is likely to be wanted for. 1994 is MCMXCIV, 2025 is MMXXV.