Number
918 in Roman numerals
918 is written CMXVIII
Type any other number or numeral below to convert it.
Above 3,999? Type the barred part in brackets, e.g. (IV)CC = 4,200.
How CMXVIII is built
Roman numerals are written one decimal place at a time, largest first.
- CMhundreds · 9C before M means 1,000 − 100 = 900. This saves writing DCCCC.
- Xtens · 1X is 10.
- VIIIones · 8V (5) plus III (3) makes 8.
900 + 10 + 8 = 918
The pair CM uses subtraction: a smaller letter before a larger one is taken away from it. Only six pairs work this way: IV, IX, XL, XC, CD and CM. More on subtraction
Mistakes to avoid
- Not DCCCCXVIII (10 letters). That adds everything up without subtraction. The Romans sometimes wrote numbers this way, and clocks still show 4 as IIII, but today CMXVIII (7 letters) is the standard.
About the number 918
- 918 is even and can be split into prime factors: 2 × 3 × 3 × 3 × 17, or in Roman numerals II × III × III × III × XVII.
- CMXVIII has 7 letters. 216 of the numbers up to 1,000 have longer numerals.
Counting from 911 to 920
Every number from 911 to 920 starts CMX (910); only the ending changes.
| Number | Roman numeral |
|---|---|
| 911 | CMXI |
| 912 | CMXII |
| 913 | CMXIII |
| 914 | CMXIV |
| 915 | CMXV |
| 916 | CMXVI |
| 917 | CMXVII |
| 918 | CMXVIII |
| 919 | CMXIX |
| 920 | CMXX |