Roman Numeral Converter

Numbers to Roman numerals

Number → Roman

Roman → Number

How it works

Roman numerals developed in ancient Rome and remained the dominant number system in Europe through the Middle Ages. They use seven letters from the Latin alphabet, each with a fixed value.

I = 1

V = 5

X = 10

L = 50

C = 100

D = 500

M = 1,000

Subtractive notation

When a smaller value appears directly before a larger one, it is subtracted rather than added. This convention was standardised in the medieval period to avoid four repeated symbols in a row (e.g. IV instead of IIII).

IV = 4

IX = 9

XL = 40

XC = 90

CD = 400

CM = 900

Why no zero, and why stop at 3,999?

Romans had no symbol for zero; their system was designed purely for counting and recording quantities, not for arithmetic. The upper limit of 3,999 is a modern convention: the largest single symbol is M (1,000), and writing four Ms in a row (MMMM) was considered non-standard. Ancient inscriptions did use a barred or to mean ×1,000, but those forms are rarely used today.