Roman Numeral Converter

What Are Roman Numerals?

Roman numerals are a numeral system that originated in ancient Rome, using combinations of letters from the Latin alphabet: I, V, X, L, C, D, and M. They remained the standard way of writing numbers throughout Europe well into the Late Middle Ages.

How Does the Converter Work?

This tool converts any whole number between 1 and 3,999 to its Roman numeral equivalent and vice versa. Just type a number or Roman numeral and the result appears instantly — no button needed.

Subtractive Notation Rules

Roman numerals use a subtractive principle for certain values:

• IV = 4 (I before V means subtract 1 from 5)
• IX = 9 (I before X means subtract 1 from 10)
• XL = 40, XC = 90, CD = 400, CM = 900

Common Uses Today

You'll still see Roman numerals used in movie credits, clock faces, book chapters, Super Bowl numbering, the Olympic Games, and to mark the year of production in film and TV.

Why Is 4000 Not Supported?

Traditional Roman numerals cap at 3,999 (MMMCMXCIX). Representing 4,000 requires either a vinculum (overline) notation or non-standard extensions which aren't universally agreed upon.