What does MCDXX mean?

MCDXX is the Roman numeral for 1,420 — 1000 + 400 + 10 + 10.

How do you write 1420 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). That gives MCDXX.

1,420 in Roman numerals

MCDXX

Number (1–3,999 for numerals)

Roman numeral

1,420 is written MCDXX in Roman numerals. That is 4 symbol groups added together, reading left to right from the largest value down.

How it breaks down

MCDXX = 1000 + 400 + 10 + 10 = 1,420
Group	Value	Subtraction	Running total
M	1,000	—	1,000
CD	400	D − C	1,400
X	10	—	1,410
X	10	—	1,420

Why the smaller symbol comes first

MCDXX 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	no
V	5	no
X	10	yes — 2×
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
Roman numeral: MCDXX
Symbol count: 5 characters
Binary: 10110001100
Hexadecimal: 58C

The numbers either side

Number	Roman numeral
1,418	MCDXVIII
1,419	MCDXIX
1,420	MCDXX ←
1,421	MCDXXI
1,422	MCDXXII

Common questions

What is 1420 in Roman numerals?: 1,420 is MCDXX.
What does MCDXX mean?: MCDXX is the Roman numeral for 1,420 — 1000 + 400 + 10 + 10.
How do you write 1420 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). That gives MCDXX.

Sources

Calculated on this page — At One Place

How these figures are compiled and checked