40 in Roman numerals
XL
The number 40 is written XL in Roman numerals.
How XL breaks down
| Symbols | Value |
|---|---|
XL | 40 |
XL | 40 |
This numeral uses the subtractive rule: a smaller symbol placed before a larger one is subtracted from it. Only six such pairs are legal — IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900).
Nearby numbers
| Number | Roman numeral |
|---|---|
| 35 | XXXV |
| 36 | XXXVI |
| 37 | XXXVII |
| 38 | XXXVIII |
| 39 | XXXIX |
| 40 | XL |
| 41 | XLI |
| 42 | XLII |
| 43 | XLIII |
| 44 | XLIV |
| 45 | XLV |
The seven symbols
I | 1 | C | 100 |
V | 5 | D | 500 |
X | 10 | M | 1,000 |
L | 50 |
40 in other notations
| Roman | XL |
| Binary | 101000 |
| Hexadecimal | 28 |
| Octal | 50 |
| Written out | forty |
Writing it by hand
Work down through the symbol values, taking as many of each as will fit before moving to the next. For 40:
XL = 40 remaining: 0The result reads XL — 2 characters, against 2 digits in Arabic numerals.
Frequently asked questions
What is 40 in Roman numerals?
XL
How do you read XL?
Work left to right, adding each symbol — except where a smaller symbol precedes a larger one, in which case it is subtracted. XL is 40.
How do you write 40 in words?
forty.
Why is there no zero?
Roman numerals have no symbol for zero. The concept reached Europe only with Hindu-Arabic numerals, centuries after the system was in use — which is a large part of why it was eventually replaced for arithmetic.