Roman Numeral Decoder
Decode a canonical subtractive Roman numeral between I and MMMCMXCIX into its integer value.
Description
Convert a canonical subtractive Roman numeral from I through MMMCMXCIX into an integer.
Roman Numeral Decoder convert a canonical subtractive Roman numeral from I through MMMCMXCIX into an integer.
Use this for validating and converting conventional modern Roman-numeral labels such as years, chapters, outlines, and clock-style examples.
When to use Roman Numeral Decoder
Use this for validating and converting conventional modern Roman-numeral labels such as years, chapters, outlines, and clock-style examples.
How it works
The parser accepts standard subtractive pairs such as IV, IX, XL, XC, CD, and CM, then adds or subtracts symbol values according to the following symbol.
Interpreting the result
Keep the input units, direction conventions, encoding, and ordering rules visible when reusing the result. Preserve the full returned value for downstream calculations and round only for presentation.
Assumptions and limitations
Historical notation varied. This strict tool rejects noncanonical repetitions, zero, negatives, overline notation, lowercase input, and values above 3,999.