Roman Numeral Converter

This numbers to roman numerals converter works both ways: type a whole number from 1 to 3999 and get its Roman numeral, or type a Roman numeral and get its number. Press Convert and the answer shows right away. Everything runs in your browser, so nothing you type leaves your device.

Range: 1 to 3999. The Romans had no zero.

How Roman numeral conversion works

  • The converter uses the seven basic letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000.
  • Letters are placed from largest to smallest. When a smaller letter comes before a larger one, it is subtracted: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900.
  • The tool accepts numbers from 1 to 3999. The Romans had no symbol for zero and no standard plain-letter way to write larger numbers.
  • Going the other way, the tool checks the letter order before it converts. A wrongly formed numeral gets a clear error instead of a wrong answer.

Common numbers: a quick reference

Useful numbers to check against the tool.

UseNumberRoman numeral
This year’s example2026MMXXVI
End of the 1900s1999MCMXCIX
A round century2000MM
The biggest it handles3999MMMCMXCIX

Solved example: 2026 to Roman numerals

Here is how 2026 becomes MMXXVI.

  1. Take the thousands: 2000 = MM.
  2. Take the tens: 20 = XX.
  3. Take the ones: 6 = VI.

Answer: 2026 = MMXXVI. Type MMXXVI back in and press Convert, and the tool gives 2026 again.

How to use this converter

  1. Pick “Number to Roman” or “Roman to Number” at the top of the tool.
  2. Type your number (1 to 3999) or Roman numeral.
  3. Press Convert and read the answer.

Limits: what this converter does not do

  • It only covers 1 to 3999. There is no zero and no negative Roman numerals.
  • It only accepts correctly formed numerals. Letter salad like “IIII” or “VX” gets an error.
  • It converts numbers only. It does not translate Latin words or dates.

Frequently asked questions

Why does this numbers to roman numerals converter stop at 3999?

Plain Roman letters only reach 3999, which is MMMCMXCIX. Writing larger numbers needs a different system, like a bar over the letters, which this tool does not support.

Is 1999 really MCMXCIX?

Yes. 1000 = M, 900 = CM, 90 = XC, and 9 = IX. Put them together and you get MCMXCIX.

Why is IIII not a valid Roman numeral?

The rules allow at most three of the same letter in a row. The number 4 is written IV, one before five, not IIII.

Did the Romans have zero?

No. There is no Roman symbol for zero, so the converter starts at 1.

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