Subnet Calculator

Network Bits

Network bits identify which subnet a device belongs to. Every device sharing the same network bits is reachable without a router. This is how LANs are formed.

Host Bits

Host bits identify the individual device within a subnet. The network address sets all of them to 0. The broadcast sets all of them to 1. Everything between is usable.

Borrowing Bits

Move the slider right by 1 and you borrow one host bit. This doubles your subnets but halves your hosts. Every bit borrowed is a trade-off - more networks, less room on each one.

Why /24 Everywhere?

A /24 gives 254 usable hosts - enough for any home or small office, and clean to read in decimal. It's one full octet for hosts. Your router is almost certainly 192.168.x.0/24 right now.