Roman Numeral Converter

Convert numbers to Roman numerals and back, from 1 to 3999.

About this tool

Type a number or a Roman numeral and get the other form. Invalid numerals are flagged.

How to use Roman Numeral Converter

  1. Enter a number from 1 to 3999 or a Roman numeral.
  2. Read the converted value.
  3. Copy it.

Frequently asked questions

Why does it stop at 3999?

Standard Roman numerals have no symbol for 5000, so 3999 (MMMCMXCIX) is the usual limit.

Is IIII valid?

It appears on some clocks, but the standard form of 4 is IV.