IPv4 Subnet Calculator
Work out the network address, broadcast address, mask, host range and size of an IPv4 CIDR block, and split it into smaller blocks.
- Addresses
- 256
- Usable hosts
- 254
- Scope
- Private / reserved
Block
- Network192.168.1.0/24
- Broadcast192.168.1.255
- Netmask255.255.255.0
- Wildcard0.0.0.255
- Host range192.168.1.1 – 192.168.1.254
- Binary11000000.10101000.00000001.01100100
Split
- 192.168.1.0/26
- 192.168.1.64/26
- 192.168.1.128/26
- 192.168.1.192/26
Files are processed in your browser and are never uploaded to a server.
How to use
Free to use with no sign-up, no install and no usage limit.
Type an address with a prefix, such as 192.168.1.100/24, and everything about that block appears at once. Leave the prefix off and it is read as a single host, /32.
A /31 is reported as two usable addresses rather than zero. RFC 3021 allows both addresses on a point-to-point link, and a calculator that subtracts the network and broadcast anyway gives an answer that contradicts a working router configuration.
The address is also shown in binary with the octets kept apart, which is the quickest way to see where the mask actually cuts when the prefix is not on an octet boundary.
Octets with a leading zero are rejected. Some tools read 010 as octal 8, so the same text can mean two different addresses; refusing it is safer than picking one reading.
The split panel divides the block into equal smaller blocks so you can see what a /24 looks like carved into four /26 networks.
Everything is computed inside your browser. No address you type is sent anywhere.