Roman Numeral Converter
Convert numbers to roman numerals and roman numerals back to numbers, with validation that rejects malformed numerals like IIII.
A Roman numeral converter translates between Arabic numbers and Roman numerals in both directions, covering 1 to 3999 - the full range classical notation can express. It follows standard subtractive form, so four is IV and ninety is XC.
Runs entirely in your browser · no signup · nothing is uploaded · updated 2026-08-29
Type a number for the numeral, or a numeral for the number. Valid range is 1 to 3999 - classical roman numerals have no zero and no notation above 3999.
How to use it
- 1.Type a number for the numeral, or a numeral for the number.
- 2.The direction is detected automatically.
- 3.Invalid numerals are rejected rather than silently guessed.
Roman numerals chart
The symbols, the subtractive pairs and the numbers people look up most. Standard notation runs from I to MMMCMXCIX (3999).
| Number | Roman numeral | Number | Roman numeral |
|---|---|---|---|
| 1 | I | 30 | XXX |
| 2 | II | 40 | XL |
| 3 | III | 50 | L |
| 4 | IV | 60 | LX |
| 5 | V | 70 | LXX |
| 6 | VI | 80 | LXXX |
| 7 | VII | 90 | XC |
| 8 | VIII | 100 | C |
| 9 | IX | 200 | CC |
| 10 | X | 300 | CCC |
| 11 | XI | 400 | CD |
| 12 | XII | 500 | D |
| 13 | XIII | 600 | DC |
| 14 | XIV | 700 | DCC |
| 15 | XV | 800 | DCCC |
| 16 | XVI | 900 | CM |
| 17 | XVII | 1000 | M |
| 18 | XVIII | 1994 | MCMXCIV |
| 19 | XIX | 2000 | MM |
| 20 | XX | 2026 | MMXXVI |
| 25 | XXV | 3999 | MMMCMXCIX |
Frequently asked questions
What is the largest roman numeral?
MMMCMXCIX, which is 3999. Classical notation has no way to write 4000 or above without the overline convention, and no symbol for zero at all.
Why is IIII wrong?
Standard notation uses subtractive pairs - four is IV, not IIII. Clock faces often use IIII for visual balance, which is a design convention rather than correct notation.
Which subtractive pairs are allowed?
Only six: IV, IX, XL, XC, CD and CM. You cannot write IL for 49 - it is XLIX.
How do I read a long numeral?
Left to right, adding each value, except where a smaller symbol sits before a larger one, in which case subtract it. MCMXCIV is 1000 + (1000−100) + (100−10) + (5−1) = 1994.
How do you write large numbers in Roman numerals?
Classical notation stops at 3999 (MMMCMXCIX). Above that, medieval scribes drew a bar over a numeral to multiply it by a thousand, a convention called vinculum, which has no standard plain-text form.
What year is MMXXVI?
2026. M is 1000, so MM is 2000, XX is 20, V is 5 and I is 1.
Is there a Roman numeral for zero?
No. The system has no zero and no negative numbers - it was built for counting and tallying, not arithmetic. Latin writers used the word nulla when they needed nothing.
Why do clock faces use IIII instead of IV?
Tradition and visual balance. IIII mirrors the VIII opposite it, and the practice predates the standardisation of subtractive notation. It is not an error, but it is not standard notation either.
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