Roman Numeral Converter

Convert integers 1–3999 to Roman numerals and back.

Roman Numeral Converter helps you convert integers 1–3999 to Roman numerals and back. Enter value, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Roman Numeral Converter calculator does Roman Numeral Converter is built for arithmetic, algebra, geometry, and number tools. Convert integers 1–3999 to Roman numerals and back. You enter value, then Simple Calculators computes the result instantly. Results use standard school and engineering formulas that run privately in your browser. How the math works Choose a Mode: Number → Roman or Roman → Number. To write a number, it is built from the largest symbols first (M = 1000, CM = 900, D = 500 … down to I = 1). To read a numeral, each letter’s value is added, but a smaller letter placed before a larger one is subtracted, so IX = 10 − 1 = 9. Numbers from 1 to 3999 are supported. The formula: Add the symbol values; a smaller symbol before a larger one is subtracted. I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000.