About this tool
This Roman numeral converter (Roman numerals to number, number to Roman numerals, Roman numeral translator) changes everyday Arabic numbers into Roman numerals and back.
It accepts whole numbers from 1 to 3999, because the standard system has no zero and needs a special bar notation above 3999. Type 2026 and you get MMXXVI; type XLII and you get 42. How do Roman numerals work?
Seven letters carry the values I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1000. Letters are normally written from largest to smallest and added together, so XVI is 10 + 5 + 1 = 16.
When a smaller letter comes before a larger one it is subtracted, so IV is 4, IX is 9, XL is 40, XC is 90, CD is 400 and CM is 900.
Only I, X and C may be subtracted, and a letter is repeated at most three times in a row, so 4 is IV and not IIII.
The converter checks this: it only reads a Roman numeral if it matches the standard form, which is why IC or VX are rejected instead of guessed. Why do people want to convert them?
Roman numerals appear in movie sequels, book chapters, clock faces, building cornerstones, outline lists, school units and monarch names. Example: 1994 is MCMXCIV, which is M (1000) + CM (900) + XC (90) + IV (4).
Remember that this is a plain converter and numbers above 3999 or below 1 are not supported.
If you need to work with other number systems, try the number base converter, and to count days between dates use the D-day tools on this site.
All conversion happens in your browser, and nothing is sent, stored or uploaded.
How to use
- Type a number from 1 to 3999, or a Roman numeral such as MMXXVI.
- The converter detects which one you typed.
- Read the result in the blue box.
- Press Copy, or tap an example chip to try it.