What range is supported?

Standard Roman numerals from 1 to 3999 (I to MMMCMXCIX). Numbers outside this range are not representable in standard Roman notation.

Does it validate Roman numerals?

Yes. The converter checks that the Roman numeral follows correct notation rules (e.g., no IIII) by round-tripping through decimal.

Roman Numeral Converter

Convert between Roman numerals and decimal numbers. Includes a reference table.

How to use: Enter a number or Roman numeral to convert between the two formats.

Decimal (1-3999)

Roman Numeral

Reference Table

4IV

9IX

10X

40XL

50L

90XC

100C

400CD

500D

900CM

1000M

Convert Roman Numerals

Type a decimal number to see its Roman representation, or enter a Roman numeral to get the decimal value. Both fields update in real-time. Includes a reference table for all basic Roman numeral symbols.

Frequently Asked Questions

What range is supported?: Standard Roman numerals from 1 to 3999 (I to MMMCMXCIX). Numbers outside this range are not representable in standard Roman notation.
Does it validate Roman numerals?: Yes. The converter checks that the Roman numeral follows correct notation rules (e.g., no IIII) by round-tripping through decimal.