Roman Numeral Converter
Convert between Arabic numbers and Roman numerals
Standard notation number
Roman Numeral
MMXXIV
Classic notation
Arabic Number
2024
Modern notation
Breakdown
MM= 2000
XX= 20
IV= 4
Century
21th century
Year Type
Leap year (if used as a year)
Roman Numeral Reference
Basic
I = 1
V = 5
X = 10
Intermediate
L = 50
C = 100
D = 500
Large
M = 1000
MM = 2000
MMM = 3000
Subtractive
IV = 4, IX = 9
XL = 40, XC = 90
CD = 400, CM = 900
How it works
Roman numerals build numbers from letters (I, V, X, L, C, D, M) by addition, with a subtraction rule for compact forms. You add values left to right, but when a smaller value sits before a larger one, you subtract it (IV = 4, not 6).
Roman numeral values
I=1 V=5 X=10 L=50 C=100 D=500 M=1000 smaller-before-larger = subtract
- subtractive pairs
- IV=4, IX=9, XL=40, XC=90, CD=400, CM=900
Worked example
- Convert MCMXCIV to a number
- M=1000, CM=900, XC=90, IV=4
MCMXCIV = 1994.
Good to know
- A symbol repeats at most three times in a row; the fourth uses subtraction (4 = IV, not IIII).
- There's no zero and no standard way to write very large numbers or fractions.
- Read left to right, adding — except where a smaller numeral precedes a larger one.
Related Calculators
Frequently Asked Questions
What are the basic Roman numerals?
I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Numbers are formed by combining these symbols.
What is the subtractive notation rule?
A smaller numeral before a larger one means subtraction: IV=4, IX=9, XL=40, XC=90, CD=400, CM=900.