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Roman Numeral Converter

Convert between Arabic numbers and Roman numerals instantly. Works both ways.

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Reference Chart

I
1
IV
4
V
5
IX
9
X
10
XL
40
L
50
XC
90
C
100
CD
400
D
500
CM
900
M
1000

How do Roman numerals work?

Roman numerals use seven basic symbols: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). Numbers are formed by combining these symbols. When a smaller symbol appears before a larger one, it's subtracted — so IV means 4 (5 minus 1) and CM means 900 (1000 minus 100). Otherwise symbols are added left to right.

Where are Roman numerals still used?

Roman numerals still appear on clock faces, movie copyright dates (MMXXVI = 2026), Super Bowl numbering (Super Bowl LIX), book chapters and volumes, monarchs and popes (King Charles III), and the faces of some prestigious buildings and institutions. The Oscars, Olympics, and many awards still use Roman numerals for their edition numbers.

Why can't Roman numerals go above 3,999?
In standard notation, M (1000) is the largest single symbol, and you can only repeat a symbol three times in a row. So the largest number expressible is MMMCMXCIX (3,999). Ancient Romans used other notations for larger numbers, but these aren't standardized today.
Why don't Roman numerals have a zero?
The Romans had no concept of zero as a number — it wasn't invented until much later by Indian mathematicians. This is one of the main limitations of the Roman numeral system compared to the Arabic numeral system we use today.