Runs locally
Roman Numerals
Convert 1–3999 to and from Roman numerals.
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Convert 1–3999 to and from Roman numerals. Runs in the browser. Nothing is uploaded.
About this tool
Convert a year, a chapter number or a clock face value into Roman numerals, or read a Roman numeral as a regular number. Works for every value from 1 to 3999.
How to use it
- 01
Type a number or a Roman numeral.
- 02
Choose the direction: encode to Roman or decode to a number.
- 03
Copy the converted value.
FAQ
Frequently asked questions
Why is the limit 3999?
Standard Roman numerals have no symbol above M (1000), so 3999 = MMMCMXCIX is the largest value written without special notation.
Are invalid numerals rejected?
Yes. Malformed sequences such as IIII or VX are reported instead of being guessed.