Roman Numeral Converter

Turn numbers into Roman numerals (up to 3999) and convert Roman numerals back into standard numbers.

All conversions happen in your browser.

How to use Roman Numeral Converter

  1. Type a number to see its Roman numeral, or type Roman numerals to see the number.
  2. The conversion appears instantly in both directions.

About this tool

Roman numerals still appear everywhere — chapter headings, clock faces, movie copyrights, Super Bowls and monarchs’ names. This converter handles both directions using the standard subtractive rules (IV, IX, XL, and so on).

Frequently asked questions

Why is the maximum 3999?
The standard form has no symbol above 1000 (M), so 3999 (MMMCMXCIX) is the largest number that can be written with the conventional rules.
Does it use modern or ancient rules?
Modern subtractive notation — the familiar IV and IX style used today.

Related tools

Number Base Converter Convert numbers between binary, octal, decimal and hexadecimal. Unit Converter Convert units of length, weight, temperature, area, volume and more. Percentage Calculator Calculate percentages — X% of a number, percentage change, and more.