---
title: "429 in Roman numerals is CDXXIX"
description: "429 in Roman numerals is CDXXIX, written as 400 + 10 + 10 + 9. How it breaks down, how to write it, and the numbers either side."
url: https://atoneplace.net/roman-numerals/429/
site: "At One Place"
---

# 429 in Roman numerals

**429 in Roman numerals: CDXXIX**

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

## How it breaks down

*CDXXIX = 400 + 10 + 10 + 9 = 429*

| Group | Value | Subtraction | Running total |
| --- | --- | --- | --- |
| CD | 400 | D − C | 400 |
| X | 10 | — | 410 |
| X | 10 | — | 420 |
| IX | 9 | X − I | 429 |

## Why the smaller symbol comes first

CDXXIX 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 | no |

## The same number, other ways

- **In words:** Four hundred twenty-nine
- **Roman numeral:** CDXXIX
- **Symbol count:** 6 characters
- **Binary:** 110101101
- **Hexadecimal:** 1AD

## The numbers either side

| Number | Roman numeral |
| --- | --- |
| 427 | CDXXVII |
| 428 | CDXXVIII |
| 429 | CDXXIX ← |
| 430 | CDXXX |
| 431 | CDXXXI |

## Common questions

### What is 429 in Roman numerals?

429 is CDXXIX.

### What does CDXXIX mean?

CDXXIX is the Roman numeral for 429 — 400 + 10 + 10 + 9.

### How do you write 429 in Roman numerals?

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

## Related pages

- [427 in Roman numerals](https://atoneplace.net/roman-numerals/427/)
- [428 in Roman numerals](https://atoneplace.net/roman-numerals/428/)
- [430 in Roman numerals](https://atoneplace.net/roman-numerals/430/)
- [431 in Roman numerals](https://atoneplace.net/roman-numerals/431/)
- [4 in Roman numerals](https://atoneplace.net/roman-numerals/4/)
- [9 in Roman numerals](https://atoneplace.net/roman-numerals/9/)
- [14 in Roman numerals](https://atoneplace.net/roman-numerals/14/)
- [19 in Roman numerals](https://atoneplace.net/roman-numerals/19/)
- [40 in Roman numerals](https://atoneplace.net/roman-numerals/40/)
- [42 in Roman numerals](https://atoneplace.net/roman-numerals/42/)
- [49 in Roman numerals](https://atoneplace.net/roman-numerals/49/)
- [50 in Roman numerals](https://atoneplace.net/roman-numerals/50/)

## Sources

- Calculated on this page — At One Place (/about/)