CDXXIX in numbers
CDXXIX = 429.
Four hundred twenty-nine written as a Roman numeral.
429 in words: Four hundred twenty-nine
CDXXIX is 429, "four hundred twenty-nine". It is built from CD (400), XX (20) and IX (9), read from the largest value down and added together. It uses the subtractive form CD and IX, where a smaller symbol placed before a larger one means one less.
Put plainly, the numeral CDXXIX in numbers is 429 ("Four hundred twenty-nine"). Type it into the converter above and it reads straight back, which is the fastest way to check a numeral you have found on a clock face, a cornerstone, a film credit or a tattoo before you trust it.
How CDXXIX is built
| Group | Value |
|---|---|
| CD | 400 |
| XX | 20 |
| IX | 9 |
| CDXXIX | 429 |
How to read CDXXIX
Roman numerals are read left to right, largest value first, adding as you go. Scanning CDXXIX one group at a time gives a running total that lands on 429:
| Read | Worth | Running total |
|---|---|---|
| CD | 400 | 400 |
| XX | 20 | 420 |
| IX | 9 | 429 |
The one place that scan can trip you up is the pairs CD and IX. A smaller letter sitting in front of a larger one is subtracted, not added, so you have to read those two letters as a single unit rather than one at a time. Treat CD as one group and the rest of CDXXIX falls into place.
Where you will see CDXXIX
Counted in order, CDXXIX is the four hundred twenty-ninth number. Read as a year, 429 falls in the 5th century AD. It sits between the round anchors CD (400) and D (500), which is the quickest way to place a numeral of this size at a glance.
Past a hundred, a numeral like CDXXIX shows up mainly in dates, formal enumeration and anywhere a large figure is written out in full. You read it exactly as you read the small ones, by taking each group from the largest value down, "four hundred twenty-nine".
- Chapters and sections: Long documents number their parts in Roman numerals: legal codes, multi-volume sets and numbered sections all reach values like CDXXIX, part 429.
- Dates and credits: Whenever a year or a copyright line is set in Roman numerals, values like CDXXIX appear in full, which is where longer numerals are most commonly seen.
Frequently asked questions
What does CDXXIX mean in Roman numerals?
CDXXIX means 429 in Roman numerals, which is "four hundred twenty-nine" in words.
What is CDXXIX in numbers?
CDXXIX in numbers is 429. Read the letters from the largest value down and add each group together.
Is CDXXIX a valid Roman numeral?
Yes. CDXXIX follows the standard rules and is the correct way to write 429.
Where is CDXXIX used?
Long documents number their parts in Roman numerals: legal codes, multi-volume sets and numbered sections all reach values like CDXXIX, part 429. Whenever a year or a copyright line is set in Roman numerals, values like CDXXIX appear in full, which is where longer numerals are most commonly seen.
What century does the year 429 fall in?
The year 429, written CDXXIX, falls in the 5th century AD.
Nearby numerals
Last updated July 22, 2026. Reviewed for accuracy against the standard rules for Roman numerals.