21 · Calculators

Roman Numeral Converter

Type a number or a Roman numeral. The converter detects which one you entered and converts it the other way.

Type 1–3999 to get a numeral, or a numeral like MCMXCIV to get the number.

Roman numeral

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How to use the roman numeral converter

  1. Type a whole number from 1 to 3,999, such as a year.
  2. Or type a Roman numeral such as MCMXCIV.
  3. The result appears straight away. Copy it with one click.

How Roman numerals work

The symbols are I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1000. They’re written largest to smallest and added together. When a smaller symbol comes before a larger one, it’s subtracted instead — but only in six pairs: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900).

The converter only accepts the standard form, so IIII or VX are flagged rather than guessed at.

Examples

2026

MMXXVI

MCMXCIV

1994

Questions

Why stop at 3,999?

Standard Roman numerals have no symbol above M (1,000), so 3,999 (MMMCMXCIX) is the largest number they can write without special notation.

Is there a Roman numeral for zero?

No. The Romans didn’t use zero as a number.

Are lowercase numerals OK?

Yes. mcmxciv is read the same as MCMXCIV.