Roman Numeral Converter
Convert between numbers and Roman numerals.
Assumptions used in this calculation
- Range: Standard Roman numerals only support values 1-3999.
About this calculator
Reading or writing Roman numerals correctly means remembering seven symbol values (I, V, X, L, C, D, M) plus six subtractive exceptions (IV, IX, XL, XC, CD, CM) that override the usual left-to-right addition, which is easy to get wrong on dates, movie credits, clock faces, or outline numbering. This calculator converts in both directions: enter a number from 1 to 3999 to get its Roman numeral, or enter a Roman numeral to get its numeric value back. For number-to-numeral conversion it works through a greedy algorithm, repeatedly subtracting the largest matching value/symbol pair (including the six subtractive combinations) until nothing remains. The 1-3999 range matches the limit of standard Roman numeral notation, since larger values traditionally require an overline (vinculum) convention that isn't standardized. That avoids manually working out where subtractive notation applies, which is the most common source of errors when converting by hand.
Worked example
1994
Result: MCMXCIV
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