How to use this calculator
- Enter or choose convert.
- The result updates as you type. Use Copy result or Share to keep it.
Method
Integer = a × 16,777,216 + b × 65,536 + c × 256 + d; a = ⌊n ÷ 2²⁴⌋ mod 256, b = ⌊n ÷ 2¹⁶⌋ mod 256, c = ⌊n ÷ 2⁸⌋ mod 256, d = n mod 256
- a.b.c.d
- the four octets, each 0–255
- n
- the integer, 0 to 4,294,967,295
Worked example
- 192 × 16,777,216 = 3,221,225,472; 168 × 65,536 = 11,010,048.
- 1 × 256 = 256 and the last octet is 1.
- Sum = 3,232,235,777 = 0xC0A80101.
192.168.1.1 is the integer 3,232,235,777, or 0xC0A80101 in hex.
What the result means
Storing addresses as unsigned integers makes range checks simple: an address is in a block if its integer lies between the block’s first and last address.
Assumptions and limits
- Octets are written in decimal; leading zeros are rejected because some software reads them as octal.
- Signed 32-bit integer columns cannot hold addresses from 128.0.0.0 upwards; use an unsigned or 64-bit type.
Questions
Why do some tools show a negative number?
They store the value as a signed 32-bit integer. Add 4,294,967,296 to a negative value to get the unsigned form shown here.
Does this work for IPv6?
No. IPv6 addresses are 128-bit; use the IPv6 Address Compression Calculator for their text forms.