Last reviewed: May 2026
Enter any CIDR block such as 192.168.1.0/24 and instantly see the full IP range it covers — network address, broadcast address, first and last usable host, and the total number of addresses.
The prefix length after the slash tells you how many bits are fixed (the network) and how many are free (the hosts). Everything below the network bits ranges from all-zeros to all-ones:
A /31 block is a special point-to-point case (RFC 3021) where both addresses are usable, and a /32 represents a single host.
| CIDR | IP Range | Total IPs | Usable Hosts |
|---|---|---|---|
| 10.0.0.0/8 | 10.0.0.0 – 10.255.255.255 | 16,777,216 | 16,777,214 |
| 172.16.0.0/12 | 172.16.0.0 – 172.31.255.255 | 1,048,576 | 1,048,574 |
| 192.168.0.0/16 | 192.168.0.0 – 192.168.255.255 | 65,536 | 65,534 |
| 192.168.1.0/24 | 192.168.1.0 – 192.168.1.255 | 256 | 254 |
| 192.168.1.0/26 | 192.168.1.0 – 192.168.1.63 | 64 | 62 |
| 192.168.1.0/30 | 192.168.1.0 – 192.168.1.3 | 4 | 2 |
192.168.1.0/24 covers 192.168.1.0 to 192.168.1.255 — 256 total addresses. The network address is 192.168.1.0, the broadcast is 192.168.1.255, and the usable host range is 192.168.1.1 to 192.168.1.254 (254 hosts).
Apply the subnet mask to the address to get the network (first) address, then set all host bits to 1 to get the broadcast (last) address. The first usable host is network + 1 and the last usable host is broadcast − 1, except for /31 and /32 blocks which have special handling.
A CIDR block of prefix length /n contains 2^(32 − n) total addresses. For example, a /24 has 2^8 = 256 addresses, a /20 has 2^12 = 4,096, and a /16 has 2^16 = 65,536. Usable hosts are typically the total minus 2 (network and broadcast).