What does CDVIII mean?

CDVIII is the Roman numeral for 408 — 400 + 5 + 1 + 1 + 1.

How do you write 408 in Roman numerals?

Take the largest value that fits and repeat until nothing is left: CD (400), then V (5), then I (1), then I (1), then I (1). That gives CDVIII.

408 in Roman numerals

CDVIII

Number (1–3,999 for numerals)

Roman numeral

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

How it breaks down

CDVIII = 400 + 5 + 1 + 1 + 1 = 408
Group	Value	Subtraction	Running total
CD	400	D − C	400
V	5	—	405
I	1	—	406
I	1	—	407
I	1	—	408

Why the smaller symbol comes first

CDVIII uses subtractive notation in one place: CD means D minus C, or 400. 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	yes — 1×
X	10	no
L	50	no
C	100	yes — 1×
D	500	yes — 1×
M	1,000	no

The same number, other ways

In words: Four hundred eight
Roman numeral: CDVIII
Symbol count: 6 characters
Binary: 110011000
Hexadecimal: 198

The numbers either side

Number	Roman numeral
406	CDVI
407	CDVII
408	CDVIII ←
409	CDIX
410	CDX

Common questions

What is 408 in Roman numerals?: 408 is CDVIII.
What does CDVIII mean?: CDVIII is the Roman numeral for 408 — 400 + 5 + 1 + 1 + 1.
How do you write 408 in Roman numerals?: Take the largest value that fits and repeat until nothing is left: CD (400), then V (5), then I (1), then I (1), then I (1). That gives CDVIII.

Sources

Calculated on this page — At One Place

How these figures are compiled and checked