---
title: "900 in Roman numerals is CM"
description: "900 in Roman numerals is CM, written as 900. How it breaks down, how to write it, and the numbers either side."
url: https://atoneplace.net/roman-numerals/900/
site: "At One Place"
---

# 900 in Roman numerals

**900 in Roman numerals: CM**

900 is written CM in Roman numerals. That is 1 symbol group added together, reading left to right from the largest value down.

## How it breaks down

*CM = 900 = 900*

| Group | Value | Subtraction | Running total |
| --- | --- | --- | --- |
| CM | 900 | M − C | 900 |

## Why the smaller symbol comes first

CM uses subtractive notation in one place: CM means M minus C, or 900. 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 | no |
| L | 50 | no |
| C | 100 | yes — 1× |
| D | 500 | no |
| M | 1,000 | yes — 1× |

## The same number, other ways

- **In words:** Nine hundred
- **Roman numeral:** CM
- **Symbol count:** 2 characters
- **Binary:** 1110000100
- **Hexadecimal:** 384

## The numbers either side

| Number | Roman numeral |
| --- | --- |
| 898 | DCCCXCVIII |
| 899 | DCCCXCIX |
| 900 | CM ← |
| 901 | CMI |
| 902 | CMII |

## Common questions

### What is 900 in Roman numerals?

900 is CM.

### What does CM mean?

CM is the Roman numeral for 900 — 900.

### How do you write 900 in Roman numerals?

Take the largest value that fits and repeat until nothing is left: CM (900). That gives CM.

## Related pages

- [898 in Roman numerals](https://atoneplace.net/roman-numerals/898/)
- [899 in Roman numerals](https://atoneplace.net/roman-numerals/899/)
- [901 in Roman numerals](https://atoneplace.net/roman-numerals/901/)
- [902 in Roman numerals](https://atoneplace.net/roman-numerals/902/)
- [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/)