Subnet Calculator

See the network, broadcast, and usable hosts for an IPv4 prefix.

IPv4 network, broadcast, mask, and usable hosts for a prefix.

IPv4 addressPrefix

/

Network

192.168.1.0

Broadcast

192.168.1.255

First host

192.168.1.1

Last host

192.168.1.254

Usable hosts

254

Mask

255.255.255.0

Calculations happen in your browser.

Worked example

192.168.1.40/24 sits in 192.168.1.0 to 192.168.1.255. The usable hosts run from .1 to .254, which is 254 addresses. The mask is 255.255.255.0.

FAQ

What is a prefix?: The number of leading 1-bits in the mask. /24 means the first 24 bits are the network.
Why are there two fewer usable hosts than addresses?: For prefixes of /30 and wider, the network address and the broadcast address are reserved. /31 and /32 are treated as special cases.
Does this support IPv6?: No. Enter an IPv4 address and a prefix from 0 to 32.