CanDoYaRuns entirely in your browser - no upload, no sign-up.
Standard subtractive notation, 1 to 3999. Converts as you type - nothing leaves your browser.
Add the symbol values from left to right, subtracting when a smaller symbol sits before a larger one: MCMXCIV is 1000 + 900 + 90 + 4 = 1994. This free Roman numeral converter works both ways instantly - type a number from 1 to 3999 or a numeral and read the result with its worked breakdown.
Each Roman symbol has a fixed value, and standard notation combines at most three repeats with six subtractive pairs (IV, IX, XL, XC, CD, CM):
| Symbol | I | V | X | L | C | D | M |
|---|---|---|---|---|---|---|---|
| Value | 1 | 5 | 10 | 50 | 100 | 500 | 1000 |
Everything runs locally in your browser. Nothing you type is uploaded or stored, the conversion updates on every keystroke, and invalid input gets a specific message (wrong letters, non-standard sequences like IIII, or numbers outside 1-3999) instead of a silent wrong answer.
Yes - 100% free, no sign-up, and no usage limits. The converter runs entirely in your browser with plain JavaScript, so it keeps working offline once the page has loaded.
No. The conversion happens locally on your device. Nothing you enter is sent to a server, stored, or shared - close the tab and it is gone.
Scan left to right and add, subtracting when a smaller symbol comes first: M = 1000, CM = 900 (100 before 1000), XC = 90 (10 before 100), IV = 4 (1 before 5). Total: 1994. The converter prints this exact breakdown for every valid numeral.
Standard notation repeats a symbol at most three times, so the largest writable value is MMMCMXCIX = 3999. The Romans wrote bigger numbers with a vinculum - an overline multiplying a symbol by 1000 - but that needs special typography, so nearly all modern converters cap at 3999.
In standard subtractive notation, 4 is IV, and this converter flags IIII as non-standard. The additive IIII does have one famous home: traditional clock faces, which use IIII for visual balance with VIII on the other side of the dial.
No. The classical system has no symbol for zero and no negative numbers - it starts at I = 1. Medieval scribes sometimes wrote N (for nulla) in tables, but it was never part of standard notation, which is why converters accept only 1 to 3999.
Convert each part separately. The year 2026 is MMXXVI; a date like 14-2-2026 becomes XIV·II·MMXXVI. For tattoos or engravings, convert the numeral back to digits here first - a misplaced subtraction is easy to miss by eye and permanent in ink.