Subnet / CIDR Calculator
Enter an IPv4 address and a prefix length (or a dotted subnet mask) to see the network address, broadcast address, usable host range, mask, wildcard, address counts and binary forms. Everything is calculated in your browser.
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 usable host
192.168.1.1
Last usable host
192.168.1.254
Total addresses
256
Usable hosts
254
Prefix length
/24
Mask in binary
11111111 11111111 11111111 00000000
Network in binary
11000000 10101000 00000001 00000000
Frequently asked questions
How do I calculate a subnet?
Supply an IPv4 address and a prefix length such as /24. The calculator ANDs the address with the subnet mask to find the network address, then derives the broadcast, host range and counts.
Why subtract two addresses?
On normal networks the first address identifies the network and the last is the broadcast address, so both are removed from the usable host count. Prefixes /31 and /32 are handled as special cases.
Can I paste a dotted subnet mask?
Yes. Enter something like 255.255.255.0 and it is converted to the equivalent /24 prefix.
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