Number
418 in Roman numerals
418 is written CDXVIII
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 CDXVIII is built
Roman numerals are written one decimal place at a time, largest first.
- CDhundreds · 4C before D means 500 − 100 = 400. This saves writing CCCC.
- Xtens · 1X is 10.
- VIIIones · 8V (5) plus III (3) makes 8.
400 + 10 + 8 = 418
The pair CD 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 CCCCXVIII (9 letters). That adds everything up without subtraction. The Romans sometimes wrote numbers this way, and clocks still show 4 as IIII, but today CDXVIII (7 letters) is the standard.
About the number 418
- 418 is even and can be split into prime factors: 2 × 11 × 19, or in Roman numerals II × XI × XIX.
- CDXVIII has 7 letters. 216 of the numbers up to 1,000 have longer numerals.
Counting from 411 to 420
Every number from 411 to 420 starts CDX (410); only the ending changes.
| Number | Roman numeral |
|---|---|
| 411 | CDXI |
| 412 | CDXII |
| 413 | CDXIII |
| 414 | CDXIV |
| 415 | CDXV |
| 416 | CDXVI |
| 417 | CDXVII |
| 418 | CDXVIII |
| 419 | CDXIX |
| 420 | CDXX |