Practical guide
How many IP addresses are in a /24?
A /24 contains 256 IPv4 addresses and usually 254 conventional host addresses. See the calculation, range, and /31 and /32 exceptions.
Updated
A /24 IPv4 network contains 256 total addresses because it leaves eight host bits: 2^(32 − 24) = 256. In a conventional subnet, 254 addresses are available to hosts after reserving the network and broadcast addresses.
Worked example
For 10.20.30.0/24, the range is 10.20.30.0 through 10.20.30.255. The conventional usable host range is 10.20.30.1 through 10.20.30.254.
| Prefix | Total addresses | Conventional usable addresses |
|---|---|---|
| /22 | 1,024 | 1,022 |
| /23 | 512 | 510 |
| /24 | 256 | 254 |
| /25 | 128 | 126 |
| /26 | 64 | 62 |
| /27 | 32 | 30 |
| /28 | 16 | 14 |
| /29 | 8 | 6 |
| /30 | 4 | 2 |
| /31 | 2 | 2 on an RFC 3021 point-to-point link |
| /32 | 1 | 1 host route |
Enter any address and prefix in the CIDR calculator, or read the full CIDR subnetting guide for the mask and bitwise method.