Subnet calculator
Give it an IPv4 or IPv6 block in CIDR notation and it works out the boundaries, the mask and how many addresses the block holds. Everything runs in your browser.
IPv4 · 192.168.1.0/24
- network
- 192.168.1.0
- broadcast
- 192.168.1.255
- last address
- 192.168.1.255
- usable range
- 192.168.1.1 – 192.168.1.254
- first usable
- 192.168.1.1
- last usable
- 192.168.1.254
- netmask
- 255.255.255.0
- wildcard
- 0.0.0.255
- prefix length
- /24
- total addresses
- 256
- usable hosts
- 254
IPv4 blocks of /30 and larger reserve their first address for the network and their last one for the broadcast, so a /24 holds 256 addresses but only 254 hosts. A /31 is a point-to-point link with two usable addresses and a /32 is a single host. IPv6 has no broadcast address, so every address in the block counts.