What does CDXLIII mean?

CDXLIII is the Roman numeral for 443 — 400 + 40 + 1 + 1 + 1.

How do you write 443 in Roman numerals?

Take the largest value that fits and repeat until nothing is left: CD (400), then XL (40), then I (1), then I (1), then I (1). That gives CDXLIII.

443 in Roman numerals

CDXLIII

Number (1–3,999 for numerals)

Roman numeral

443 is written CDXLIII in Roman numerals. That is 5 symbol groups added together, reading left to right from the largest value down.

How it breaks down

CDXLIII = 400 + 40 + 1 + 1 + 1 = 443
Group	Value	Subtraction	Running total
CD	400	D − C	400
XL	40	L − X	440
I	1	—	441
I	1	—	442
I	1	—	443

Why the smaller symbol comes first

CDXLIII uses subtractive notation in 2 places: CD means D minus C, or 400; 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 — 1×
D	500	yes — 1×
M	1,000	no

The same number, other ways

In words: Four hundred forty-three
Roman numeral: CDXLIII
Symbol count: 7 characters
Binary: 110111011
Hexadecimal: 1BB

The numbers either side

Number	Roman numeral
441	CDXLI
442	CDXLII
443	CDXLIII ←
444	CDXLIV
445	CDXLV

Common questions

What is 443 in Roman numerals?: 443 is CDXLIII.
What does CDXLIII mean?: CDXLIII is the Roman numeral for 443 — 400 + 40 + 1 + 1 + 1.
How do you write 443 in Roman numerals?: Take the largest value that fits and repeat until nothing is left: CD (400), then XL (40), then I (1), then I (1), then I (1). That gives CDXLIII.

Sources

Calculated on this page — At One Place

How these figures are compiled and checked