What does CDXCVII mean?

CDXCVII is the Roman numeral for 497 — 400 + 90 + 5 + 1 + 1.

How do you write 497 in Roman numerals?

Take the largest value that fits and repeat until nothing is left: CD (400), then XC (90), then V (5), then I (1), then I (1). That gives CDXCVII.

497 in Roman numerals

CDXCVII

Number (1–3,999 for numerals)

Roman numeral

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

How it breaks down

CDXCVII = 400 + 90 + 5 + 1 + 1 = 497
Group	Value	Subtraction	Running total
CD	400	D − C	400
XC	90	C − X	490
V	5	—	495
I	1	—	496
I	1	—	497

Why the smaller symbol comes first

CDXCVII uses subtractive notation in 2 places: CD means D minus C, or 400; 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 — 2×
V	5	yes — 1×
X	10	yes — 1×
L	50	no
C	100	yes — 2×
D	500	yes — 1×
M	1,000	no

The same number, other ways

In words: Four hundred ninety-seven
Roman numeral: CDXCVII
Symbol count: 7 characters
Binary: 111110001
Hexadecimal: 1F1

The numbers either side

Number	Roman numeral
495	CDXCV
496	CDXCVI
497	CDXCVII ←
498	CDXCVIII
499	CDXCIX

Common questions

What is 497 in Roman numerals?: 497 is CDXCVII.
What does CDXCVII mean?: CDXCVII is the Roman numeral for 497 — 400 + 90 + 5 + 1 + 1.
How do you write 497 in Roman numerals?: Take the largest value that fits and repeat until nothing is left: CD (400), then XC (90), then V (5), then I (1), then I (1). That gives CDXCVII.

Sources

Calculated on this page — At One Place

How these figures are compiled and checked