🏛️ Roman Numeral Converter

Convert numbers to Roman numerals and Roman numerals back to numbers — both directions.

About this tool

Type a number to get its Roman numeral, or type a Roman numeral to get the number. Standard subtractive notation (IV, IX, XL, XC, CD, CM) is used, and values above 3,999 use overline notation (a bar over a letter multiplies it by 1,000), supporting up to 3,999,999. Invalid numerals are flagged.

Handy for clock faces, copyright dates, book chapters, Super Bowl numbers, and outlines. Everything runs locally in your browser.

Number
Roman numeral
Reference
I1
V5
X10
L50
C100
D500
M1,000
5,000
10,000
1,000,000
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