What does CCXLIII mean?

CCXLIII is the Roman numeral for 243 — 100 + 100 + 40 + 1 + 1 + 1.

How do you write 243 in Roman numerals?

Take the largest value that fits and repeat until nothing is left: C (100), then C (100), then XL (40), then I (1), then I (1), then I (1). That gives CCXLIII.

243 in Roman numerals

CCXLIII

Number (1–3,999 for numerals)

Roman numeral

243 is written CCXLIII in Roman numerals. That is 6 symbol groups added together, reading left to right from the largest value down.

How it breaks down

CCXLIII = 100 + 100 + 40 + 1 + 1 + 1 = 243
Group	Value	Subtraction	Running total
C	100	—	100
C	100	—	200
XL	40	L − X	240
I	1	—	241
I	1	—	242
I	1	—	243

Why the smaller symbol comes first

CCXLIII uses subtractive notation in one place: XL means L minus X, or 40. 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 — 3×
V	5	no
X	10	yes — 1×
L	50	yes — 1×
C	100	yes — 2×
D	500	no
M	1,000	no

The same number, other ways

In words: Two hundred forty-three
Roman numeral: CCXLIII
Symbol count: 7 characters
Binary: 11110011
Hexadecimal: F3

The numbers either side

Number	Roman numeral
241	CCXLI
242	CCXLII
243	CCXLIII ←
244	CCXLIV
245	CCXLV

Common questions

What is 243 in Roman numerals?: 243 is CCXLIII.
What does CCXLIII mean?: CCXLIII is the Roman numeral for 243 — 100 + 100 + 40 + 1 + 1 + 1.
How do you write 243 in Roman numerals?: Take the largest value that fits and repeat until nothing is left: C (100), then C (100), then XL (40), then I (1), then I (1), then I (1). That gives CCXLIII.

Sources

Calculated on this page — At One Place

How these figures are compiled and checked