Convert between numbers and Roman numerals (1–3999), with strict validation of numerals.

How it works

Symbol	I	V	X	L	C	D	M
Value	1	5	10	50	100	500	1000

Symbols are written largest first and added up. A smaller symbol before a larger one is subtracted, but only in six pairs: IV (4), IX (9), XL (40), XC (90), CD (400), CM (900).

The converter is strict: it accepts only the standard form, so IIII, VX or IC are rejected with the correct spelling suggested. (IIII still appears on clock faces, by tradition.) Without a bar notation, the largest standard numeral is MMMCMXCIX = 3999.

References

Roman numerals — Wikipedia

Roman Numeral Converter

How it works

References

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