Roman Numerals

Roman numerals are combinations of seven letters (I, V, X, L, C, D, M) that represent numeric values. This tool helps you understand and convert between Arabic numbers and Roman numerals, including the rules for addition and subtraction.

Arabic Number	Roman Numeral	Calculation
1	I	1
2	II	1 + 1
3	III	1 + 1 + 1
4	IV	-1 + 5
5	V	5
6	VI	5 + 1
7	VII	5 + 1 + 1
8	VIII	5 + 1 + 1 + 1
9	IX	-1 + 10
10	X	10
11	XI	10 + 1
12	XII	10 + 1 + 1
15	XV	10 + 5
20	XX	10 + 10
30	XXX	10 + 10 + 10
40	XL	-10 + 50
50	L	50
90	XC	-10 + 100
100	C	100
400	CD	-100 + 500
500	D	500
900	CM	-100 + 1000
1000	M	1000
1977	MCMLXXVII	1000 + (-100 + 1000) + 50 + 10 + 10 + 5 + 1 + 1
1982	MCMLXXXII	1000 + (-100 + 1000) + 50 + 10 + 10 + 10 + 1 + 1
5000	V̄	5 × 1000

Roman Numeral Rules

The Seven Roman Numeral Letters

I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1000

Rules for Combining

Smaller numbers before larger numbers are subtracted (e.g., IV = 4, IX = 9)
Smaller numbers after larger numbers are added (e.g., VI = 6, XI = 11)
Roman numerals have no zero
Large numbers are indicated with a horizontal line above them, multiplying the value by 1000