IP Subnet Calculator
IPv4 subnet math from CIDR — runs entirely in your browser, nothing is sent to a server.
Network address
192.168.1.0
Broadcast address
192.168.1.255
Subnet mask
255.255.255.0
Wildcard mask
0.0.0.255
First host address
192.168.1.1
Last host address
192.168.1.254
Total addresses
256
Usable hosts
254
Frequently asked questions
What is CIDR notation?⌄
A notation like 192.168.1.0/24, where the number after the slash is the subnet prefix length in bits. The larger the prefix, the fewer addresses in the subnet: /24 gives 256 addresses, /30 gives just 4.
Why are there fewer usable hosts than total addresses?⌄
The first address in the range is reserved for the network address, and the last for the broadcast address. Neither can be assigned to a device, so 2 are subtracted from the total (except for /31 and /32 subnets).