Roman Numeral Converter
Convert between decimal numbers and Roman numerals in both directions. Enter a number (1-3999) or a Roman numeral string and get the equivalent instantly, with the symbol table on hand.
Conversion
Result
Symbol equivalence
I
1
V
5
X
10
L
50
C
100
D
500
M
1000
Popular lookups
How to use: Roman numerals
- 1Type a decimal number (1–3999) or a Roman numeral.
- 2The conversion happens instantly in both directions.
- 3Copy the result.
What is it for?
- Read years on monuments, movie credits or books.
- Write centuries, chapters or tattoos in Roman numerals.
- Do math and history homework.
How Roman numerals work
Symbols
I=1, V=5, X=10, L=50, C=100, D=500, M=1000. They are written from largest to smallest and added; if a smaller symbol precedes a larger one it is subtracted (IV=4, IX=9, XL=40, CM=900).
Limits
With standard notation the maximum is 3999 (MMMCMXCIX). There is no zero, and 4 is written IV (though old clock faces show IIII).
Modern uses
Centuries, chapters, kings and popes (Henry VIII), numbered films and events, clock faces and ornamental dates.
Related tools
Frequently asked questions
What's the highest number it supports?+
3999 (MMMCMXCIX), following classical Roman notation. Higher values need extended notation with vinculum (overlines).
Why is 90 written XC and not LXXXX?+
Because of the subtractive rule: a smaller numeral before a larger one means subtraction. The tool only accepts standard notation.