What does MCXCI mean?

MCXCI is the Roman numeral for 1,191 — 1000 + 100 + 90 + 1.

How do you write 1191 in Roman numerals?

Take the largest value that fits and repeat until nothing is left: M (1000), then C (100), then XC (90), then I (1). That gives MCXCI.

1,191 in Roman numerals

MCXCI

Number (1–3,999 for numerals)

Roman numeral

1,191 is written MCXCI in Roman numerals. That is 4 symbol groups added together, reading left to right from the largest value down.

How it breaks down

MCXCI = 1000 + 100 + 90 + 1 = 1,191
Group	Value	Subtraction	Running total
M	1,000	—	1,000
C	100	—	1,100
XC	90	C − X	1,190
I	1	—	1,191

Why the smaller symbol comes first

MCXCI uses subtractive notation in one place: XC means C minus X, or 90. A smaller symbol placed before a larger one is subtracted from it rather than added, which is why IX is nine and not eleven.

Only six such pairs are valid — IV, IX, XL, XC, CD and CM. That restriction is what makes the notation unambiguous: IIII and IC both look like they should work, but neither is standard, and only one spelling of any number is correct.

The symbols

Symbol	Value	Used here
I	1	yes — 1×
V	5	no
X	10	yes — 1×
L	50	no
C	100	yes — 2×
D	500	no
M	1,000	yes — 1×

The same number, other ways

In words: One thousand one hundred ninety-one
Roman numeral: MCXCI
Symbol count: 5 characters
Binary: 10010100111
Hexadecimal: 4A7

The numbers either side

Number	Roman numeral
1,189	MCLXXXIX
1,190	MCXC
1,191	MCXCI ←
1,192	MCXCII
1,193	MCXCIII

Common questions

What is 1191 in Roman numerals?: 1,191 is MCXCI.
What does MCXCI mean?: MCXCI is the Roman numeral for 1,191 — 1000 + 100 + 90 + 1.
How do you write 1191 in Roman numerals?: Take the largest value that fits and repeat until nothing is left: M (1000), then C (100), then XC (90), then I (1). That gives MCXCI.

Sources

Calculated on this page — At One Place

How these figures are compiled and checked