Subnet calculator
Calculate network, mask, broadcast and hosts for an IPv4/CIDR block locally in your browser.
10.0.0.0/8
172.16.0.0/12
192.168.0.0/16
192.168.1.0/24
192.168.1.0/28
192.168.1.0/30
How to interpret
A /24 has 256 addresses and 254 traditional hosts. /31 is treated as a point-to-point link with two addresses; /32 as a single-host route. Network and broadcast are not ordinary hosts for prefixes up to /30. Document gateways, reserve growth space and avoid overlaps between LAN, VPN and cloud before creating rules.