Roman numerals to integers

Decode standard Roman numerals to decimal integers.

Numbers Stateless

Maximum input length per field: 32 Unicode code points. See the operation limits in the instructions.

Quick guide

Try it with your own data when you’re ready.

Try an example

You enter

Roman numeral
MCMXCIV

You get

1994
How it works & limits

Accepts standard subtractive notation from I to MMMCMXCIX (1–3999), ignoring letter case and outer whitespace. Noncanonical forms such as IIII, VX or IC are rejected.

Example: MCMXCIV becomes 1994. Zero, fractions and overbar notation are not supported.