Roman Numeral Converter
Free, with no sign up. Conversion runs in your browser; your entries stay on this device. The converter accepts canonical Roman forms only, from I (1) through MMMCMXCIX (3999).
Your result
Formula: use the largest numeral value that fits; subtractive pairs are IV, IX, XL, XC, CD and CM.
Worked example
2026 = MMXXVI: 2000 (MM) + 20 (XX) + 6 (VI). Conversely, MCMXCIV = 1994.
Roman numerals here follow the standard subtractive notation using I, V, X, L, C, D and M. The converter checks the canonical spelling by converting the value back.
How it works
Canonical subtractive Roman notation uses the six pairs IV, IX, XL, XC, CD and CM.
How to use this tool
Use the fields below and select the action button to calculate.
Frequently asked questions
Can I enter lowercase Roman numerals?
Yes. Lowercase input is normalized to uppercase, then checked against canonical Roman spelling.
Which Roman numeral forms are accepted?
Canonical forms from I to MMMCMXCIX are accepted; forms such as IIII, VV and IC are rejected.
Does this upload my number?
No. The calculation runs in your browser; your input stays on this device.