Type a number to get its Roman numeral, or type a Roman numeral such as MCMXCIV to get the number. Non-standard forms are flagged with the correct spelling.
Roman numerals use seven letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1,000. A number is written from the largest value down, and a smaller letter placed before a larger one is subtracted, which gives IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900).
Each value has exactly one standard spelling, so the converter rejects forms such as IIII or MIM and shows the standard one instead.
The box on the Convert page answers the same questions as you type, for example “120000 in words”, “1994 in roman”, “255 in binary” or “0.375 as a fraction”.
| Number | Roman numeral |
|---|---|
| 1 | I |
| 4 | IV |
| 5 | V |
| 9 | IX |
| 10 | X |
| 14 | XIV |
| 19 | XIX |
| 40 | XL |
| 49 | XLIX |
| 50 | L |
| 90 | XC |
| 99 | XCIX |
| 100 | C |
| 400 | CD |
| 500 | D |
| 900 | CM |
| 1,000 | M |
| 1,984 | MCMLXXXIV |
| 1,999 | MCMXCIX |
| 2,000 | MM |
| 2,025 | MMXXV |
| 2,026 | MMXXVI |
| 3,999 | MMMCMXCIX |
Standard Roman numerals use subtraction for 4s and 9s: IV, IX, XL, XC, CD and CM. IIII appears on some clock faces but is not the standard form, so the converter suggests IV.
With the seven standard letters the largest is MMMCMXCIX, which is 3,999. Larger numbers were written with a bar over a letter to multiply it by 1,000, which is outside the standard set.
Add the letter values from left to right, but subtract a letter that stands before a larger one. MCMXCIV is 1,000 + 900 + 90 + 4 = 1,994.