Subnet Calculator
Calculate network address, broadcast address, and host range for any IP subnet. Essential tool for network administrators and IT professionals.
Enter an IP address to see subnet details.
How It Works
Subnetting divides an IP network into smaller segments. The CIDR notation (e.g., /24) indicates how many bits are used for the network portion. The remaining bits are for host addresses. A /24 network has 256 total addresses (254 usable hosts).
Frequently Asked Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation like /24 indicates how many bits of the 32-bit IP address are used for the network prefix. /24 means 24 network bits and 8 host bits (256 addresses).
Why are there 2 fewer usable hosts?
Two addresses are reserved: the network address (all host bits = 0) identifies the network itself, and the broadcast address (all host bits = 1) sends to all hosts on the network.
What's the wildcard mask for?
Wildcard masks are used in access control lists (ACLs) on routers. They're the inverse of subnet masks. Where the subnet mask has 1s, the wildcard has 0s, and vice versa.