What does MCDXXIX mean?

MCDXXIX is the Roman numeral for 1,429 — 1000 + 400 + 10 + 10 + 9.

How do you write 1429 in Roman numerals?

Take the largest value that fits and repeat until nothing is left: M (1000), then CD (400), then X (10), then X (10), then IX (9). That gives MCDXXIX.

1,429 in Roman numerals

MCDXXIX

Number (1–3,999 for numerals)

Roman numeral

1,429 is written MCDXXIX in Roman numerals. That is 5 symbol groups added together, reading left to right from the largest value down.

How it breaks down

MCDXXIX = 1000 + 400 + 10 + 10 + 9 = 1,429
Group	Value	Subtraction	Running total
M	1,000	—	1,000
CD	400	D − C	1,400
X	10	—	1,410
X	10	—	1,420
IX	9	X − I	1,429

Why the smaller symbol comes first

MCDXXIX uses subtractive notation in 2 places: CD means D minus C, or 400; IX means X minus I, or 9. 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 — 3×
L	50	no
C	100	yes — 1×
D	500	yes — 1×
M	1,000	yes — 1×

The same number, other ways

In words: One thousand four hundred twenty-nine
Roman numeral: MCDXXIX
Symbol count: 7 characters
Binary: 10110010101
Hexadecimal: 595

The numbers either side

Number	Roman numeral
1,427	MCDXXVII
1,428	MCDXXVIII
1,429	MCDXXIX ←
1,430	MCDXXX
1,431	MCDXXXI

Common questions

What is 1429 in Roman numerals?: 1,429 is MCDXXIX.
What does MCDXXIX mean?: MCDXXIX is the Roman numeral for 1,429 — 1000 + 400 + 10 + 10 + 9.
How do you write 1429 in Roman numerals?: Take the largest value that fits and repeat until nothing is left: M (1000), then CD (400), then X (10), then X (10), then IX (9). That gives MCDXXIX.

Sources

Calculated on this page — At One Place

How these figures are compiled and checked