Number
440 in Roman numerals
440 is written CDXL
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 CDXL 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.
- XLtens · 4X before L means 50 − 10 = 40. This saves writing XXXX.
400 + 40 = 440
The pairs CD and XL use 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 CCCCXXXX (8 letters). That adds everything up without subtraction. The Romans sometimes wrote numbers this way, and clocks still show 4 as IIII, but today CDXL (4 letters) is the standard.
- There's no letter for zero. The zero is simply left out, which is why 440 has 2 parts, not 3.
About the number 440
- 440 is even and can be split into prime factors: 2 × 2 × 2 × 5 × 11, or in Roman numerals II × II × II × V × XI.
- CDXL has 4 letters. 784 of the numbers up to 1,000 have longer numerals.
Counting from 431 to 440
Every number from 431 to 440 starts CDX (410); only the ending changes.
| Number | Roman numeral |
|---|---|
| 431 | CDXXXI |
| 432 | CDXXXII |
| 433 | CDXXXIII |
| 434 | CDXXXIV |
| 435 | CDXXXV |
| 436 | CDXXXVI |
| 437 | CDXXXVII |
| 438 | CDXXXVIII |
| 439 | CDXXXIX |
| 440 | CDXL |