IP Subnet Calculator
Enter an IPv4 address in CIDR notation to get the network address, broadcast, usable host range and netmask instantly.
How subnetting works
The /26 in 192.168.1.130/26 says the first 26 bits identify the network and the remaining 6 bits identify hosts within it — giving 2⁶ = 64 addresses, of which 62 are usable (the first is the network address, the last is broadcast). Routers use the netmask to decide whether a destination is local or needs forwarding.
Common prefixes
/8— 16,777,214 hosts (255.0.0.0), classic "Class A"/16— 65,534 hosts (255.255.0.0)/24— 254 hosts (255.255.255.0), the typical home LAN/30— 2 hosts, point-to-point links;/31— RFC 3021 point-to-point;/32— a single host
Frequently asked questions
Why are two addresses per subnet unusable?
The all-zeros host address names the network itself and the all-ones address is the broadcast. Exceptions: /31 links use both addresses (RFC 3021) and /32 denotes exactly one host.
What are the private IP ranges?
10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 (RFC 1918) — plus 100.64.0.0/10 for carrier-grade NAT.
Last updated: 2026-07-12