Subnet & CIDR calculator

Enter an address with a prefix or netmask to get the network, broadcast address, usable host range and mask. Works for IPv4 and IPv6, right in your browser.

IP address with a prefix or netmask

Try:

Network: 192.168.1.0/24
Netmask: 255.255.255.0
Wildcard mask: 0.0.0.255
Broadcast: 192.168.1.255
First usable: 192.168.1.1
Last usable: 192.168.1.254
Usable hosts: 254
Total addresses: 256
Address type: Private (RFC 1918)
Netmask in binary: 11111111.11111111.11111111.00000000

Good to know

What does /24 mean?: CIDR notation: the first 24 bits are the network and the rest identify hosts. A /24 has 256 addresses, 254 of them usable, because the first is the network address and the last the broadcast address.
Why do /31 and /32 have no broadcast?: A /31 is a two-address link between routers (RFC 3021), and a /32 is a single host, so both use every address.
Which ranges are private?: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 (RFC 1918), plus 100.64.0.0/10 for carrier-grade NAT. They aren't reachable from the internet.

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