Roman Numeral Converter
Convert numbers to Roman numerals and back, up to 3,999,999.
About this roman numeral converter
Roman numerals use seven letters — I, V, X, L, C, D and M — combined by addition, with a subtractive rule for the awkward cases: IV is four rather than IIII, IX is nine, XL is forty.
Standard numerals stop at 3,999 because there is no single symbol for five thousand. Beyond that, a bar over a numeral multiplies it by a thousand; this tool uses parentheses to show that, so (V) is five thousand.
How to use it
- Type a number to get the numeral, or type a numeral to get the number.
- The breakdown shows which symbol contributed what.
- Both directions validate as you type and tell you what is wrong if the numeral is malformed.
Roman Numeral Converter — FAQ
Why is four IV and not IIII?
The subtractive rule: a smaller symbol before a larger one is subtracted. IIII does appear historically, and still does on some clock faces, but IV is the standard modern form.
What is the largest Roman numeral?
3,999 (MMMCMXCIX) in the standard system. Larger values need the vinculum — a bar meaning multiply by a thousand — which this tool writes as parentheses.
Is there a zero?
No. The system has no symbol for zero and no way to express negative numbers or fractions of this kind.