Enter a whole number such as 2003, or a Roman numeral such as MMIII, then click Convert. Your input will translate instantly.

The input must be in the range of 1 - 4999, or I to MMMMCMXCIX.

A smaller number in front of a larger number means subtraction, all else means addition. For example, IV means 4, VI means 6.

You would not put more than one smaller number in front of a larger number to subtract. For example, IIV would not mean 3.

You must separate ones, tens, hundreds, and thousands as separate items. That means that 99 is XCIX, 90 + 9, but never should be written as IC. Similarly, 999 cannot be IM and 1999 cannot be MIM.