Roman Numeral Converter

Convert between decimal (1–3999) and Roman numerals (I–MMMCMXCIX) with subtractive notation.

Convert Numerals

Decimal ↔ Roman

Decimal Number (1–3999)

Roman Numeral

Result

Breakdown

Quick Reference

Rules

Subtractive notation: IV=4, IX=9, XL=40, XC=90, CD=400, CM=900

Additive: VI=6, XI=11, LX=60, etc.

Related Calculators

Pro Tips

Roman numerals have no symbol for zero or negative numbers.

Standard form only goes up to 3999 (MMMCMXCIX). Larger numbers used overlining.

Subtractive notation: a smaller symbol before a larger one means subtract (IV = 4).