IP Subnet Calculator
Netmask, network, broadcast, and usable hosts from an IP and CIDR.
Calculate the netmask, network address, broadcast address, and usable host range for an IPv4 address and CIDR prefix.
Frequently asked questions
What does the CIDR prefix (the /24 part) mean?
It's the number of bits used for the network portion of the address — a /24 means the first 24 bits identify the network, leaving 8 bits (256 addresses) for hosts.
Why is the usable host count 2 less than the total?
The first address in a subnet is reserved as the network address, and the last is reserved as the broadcast address — neither can be assigned to a device.