Convert a number into Roman numerals (1 to 3999) or translate Roman numerals back into a number. Both directions validate your input.
Results update as you type. Uses standard subtractive notation (IV, IX, XL, XC, CD, CM).
Break the number into thousands, hundreds, tens, and ones, then replace each with its Roman symbol using subtractive notation. For example, 1994 = M (1000) + CM (900) + XC (90) + IV (4), which is MCMXCIV.
Subtractive notation places a smaller symbol before a larger one to subtract it: IV is 4 (5 − 1), IX is 9, XL is 40, XC is 90, CD is 400, and CM is 900. It avoids writing four of the same symbol in a row.
Standard Roman numerals use the symbols I, V, X, L, C, D, and M, and the largest is M (1000). Without overline notation for larger values, the biggest number you can write conventionally is 3999 (MMMCMXCIX), and there is no symbol for zero.