Roman Numeral to Number Converter
Roman Numeral to Number Converter
Enter a Roman numeral (using letters I, V, X, L, C, D, M) to instantly see its decimal number value — useful for reading movie copyright years, clock faces, or historical dates.
Reading a Roman numeral works left to right, adding each symbol's value as you go — except when a smaller symbol appears immediately before a larger one, in which case it's subtracted instead of added. MCMXCIV, the classic example seen at the end of many older films, breaks down as M (1000) + CM (900) + XC (90) + IV (4), adding up to 1994 — untangling that subtractive notation by eye is exactly the kind of thing this converter does instantly, and both uppercase and lowercase input work identically.
- Method: add each symbol's value left to right, but subtract a symbol if it comes right before a larger one.
- Example: MCMXCIV = M(1000) + CM(900) + XC(90) + IV(4) = 1994.
- Case-insensitive: both uppercase (MCMXCIV) and lowercase (mcmxciv) work the same way.
What number is XLII?
XL=40, II=2, so XLII = 42.
What if I enter an invalid Roman numeral like "IIII" or "VV"?
This calculator parses the symbols using the standard subtraction rule and will still return a value, but it may not match standard Roman numeral notation (which would write 4 as "IV", not "IIII").
Roman Numeral to Number Converter
Enter a Roman numeral (using letters I, V, X, L, C, D, M) to instantly see its decimal number value — useful for reading movie copyright years, clock faces, or historical dates.
Reading a Roman numeral works left to right, adding each symbol's value as you go — except when a smaller symbol appears immediately before a larger one, in which case it's subtracted instead of added. MCMXCIV, the classic example seen at the end of many older films, breaks down as M (1000) + CM (900) + XC (90) + IV (4), adding up to 1994 — untangling that subtractive notation by eye is exactly the kind of thing this converter does instantly, and both uppercase and lowercase input work identically.
- Method: add each symbol's value left to right, but subtract a symbol if it comes right before a larger one.
- Example: MCMXCIV = M(1000) + CM(900) + XC(90) + IV(4) = 1994.
- Case-insensitive: both uppercase (MCMXCIV) and lowercase (mcmxciv) work the same way.
What number is XLII?
XL=40, II=2, so XLII = 42.
What if I enter an invalid Roman numeral like "IIII" or "VV"?
This calculator parses the symbols using the standard subtraction rule and will still return a value, but it may not match standard Roman numeral notation (which would write 4 as "IV", not "IIII").