Roman Numeral Converter

How it works

Numbers convert to Roman by repeatedly subtracting the largest available value (M=1000, CM=900, D=500, CD=400, …, IV=4, I=1) until zero. Roman numerals parse with a strict pattern that rejects invalid sequences like "IIII" or "VV".

Frequently asked

Why is the maximum 3,999?

Standard Roman numerals only go to 3,999 (MMMCMXCIX). Larger values historically used vinculum (a bar over the letter to multiply by 1000) but support varies, so we cap at 3,999.

Is "IIII" or "IV" the correct way to write 4?

Both have been used historically, but the subtractive form (IV) is the modern standard. We output IV. We accept IIII as input for backwards compatibility (clock faces still use it).

Why are some Super Bowls written L instead of 50?

Tradition. Roman numerals add gravitas in titles, monuments, and dates — the practical use disappeared centuries ago, but the cultural use persists.