What is CIDR notation?

CIDR (Classless Inter-Domain Routing) notation expresses an IP address along with its associated network prefix length, e.g. 192.168.1.0/24 where /24 means 24 bits are the network portion, leaving 8 bits for host addresses (254 usable hosts).

How is the broadcast address calculated?

The broadcast address is calculated by performing a bitwise OR of the network address with the inverted subnet mask (wildcard mask). All host bits are set to 1, making it the last address in the subnet.

What are usable hosts?

Usable hosts are all IP addresses in the subnet except the network address (first) and broadcast address (last). A /24 subnet has 256 total addresses but only 254 usable host addresses.

Subnet Calculator

Calculate network address, broadcast, hosts, and subnet mask from IP/CIDR notation.

Network Address192.168.1.0

Subnet Mask255.255.255.0

Wildcard Mask0.0.0.255

Broadcast Address192.168.1.255

First Usable Host192.168.1.1

Last Usable Host192.168.1.254

Total Hosts256

Usable Hosts254

CIDR Prefix/24

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FAQ

What is CIDR notation?: CIDR (Classless Inter-Domain Routing) notation expresses an IP address along with its associated network prefix length, e.g. 192.168.1.0/24 where /24 means 24 bits are the network portion, leaving 8 bits for host addresses (254 usable hosts).
How is the broadcast address calculated?: The broadcast address is calculated by performing a bitwise OR of the network address with the inverted subnet mask (wildcard mask). All host bits are set to 1, making it the last address in the subnet.
What are usable hosts?: Usable hosts are all IP addresses in the subnet except the network address (first) and broadcast address (last). A /24 subnet has 256 total addresses but only 254 usable host addresses.

Enter an IP address and CIDR prefix (e.g. 192.168.1.0/24) to instantly calculate network address, broadcast address, first and last usable host, total host count, wildcard mask, and subnet mask. All results are copyable. Useful for network planning, firewall rules, and infrastructure configuration.