What is the largest number this supports?

It converts whole numbers from 1 to 3999 (I to MMMCMXCIX), the standard range using the basic letters I, V, X, L, C, D and M without overline notation.

How do Roman numerals like IV and IX work?

When a smaller symbol comes before a larger one it is subtracted — IV is 5 − 1 = 4 and IX is 10 − 1 = 9. Otherwise symbols are added left to right.

Is anything uploaded?

No — the conversion happens entirely in your browser with no network calls.

Roman Numerals Chart

Convert numbers to Roman numerals, plus a full chart.

Roman numerals chart and converter

Type any whole number from 1 to 3999 and get its Roman numeral instantly, or use the reference below: the symbol values (I=1, V=5, X=10, L=50, C=100, D=500, M=1000) and a chart of common conversions from 1 to 2026.

Subtractive pairs like IV (4) and IX (9) place a smaller symbol before a larger one to subtract. Everything runs in your browser.