What range is supported?

1 to 3999 (I to MMMCMXCIX). Roman numerals don't have a standard representation above 3999.

How does it handle invalid input?

Invalid Roman numerals show an error. Invalid numbers outside 1-3999 are rejected.

Convert Roman numerals to numbers and numbers to Roman numerals. Free online converter.

Arabic Number

Range: 1 - 3999

Roman Numeral

Characters: I, V, X, L, C, D, M

Convert between Roman numerals and Arabic numbers instantly.

Both directions

Roman to Arabic and Arabic to Roman.

Validation

Detects invalid Roman numerals.