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IP/24SubnetLens

Subnet calculator

Network, usable range, broadcast, mask and wildcard for any IPv4 network — shown as a block you can resize and split.

Try
192.168.1.0/24
Entered192.168.1.42
254usable addresses
First usable
192.168.1.1
Last usable
192.168.1.254
Subnet 192 dot 168 dot 1 dot 0 slash 24. 256 total addresses, 254 usable host addresses. First usable 192 dot 168 dot 1 dot 1, last usable 192 dot 168 dot 1 dot 254. Broadcast 192 dot 168 dot 1 dot 255. The entered address 192 dot 168 dot 1 dot 42 sits at offset 42 inside the block.
Usable hosts256 total
254
Common
Usable hosts
254
256 total
Bits
24 network/8 host

What the four answers mean

The network address is the first address in the block and names the block itself. The broadcast address is the last, and reaches everything on the link at once. Neither can be given to a host, which is why a /24 offers 254 usable addresses out of 256 — the usable range is everything between the two.

Two sizes that break the rule

A /31 has only two addresses, so the usual reservation would leave none at all. RFC 3021 defines it for point-to-point links, where both ends are usable. A /32 is a single address with no range at all — a host route, a loopback or a firewall entry. SubnetLens counts both correctly rather than showing you a negative host count.