CIDR and Subnets Explained: Network, Broadcast, Usable Range, and Splitting for IPv4 and IPv6

Configuring a network or firewall means knowing how many addresses a range holds and where it starts and ends. CIDR is the short way of writing such a range.

Reading CIDR

192.168.1.10/24 means the address 192.168.1.10 where the first 24 bits are the network part. The larger the number after the slash, the smaller the subnet.

What you get

• Network, broadcast, subnet mask and wildcard.
• The usable range and host count.
• The address type, such as private, public or loopback.
• Splitting into smaller subnets, and checking whether an IP is inside.
• IPv6 support.

Pure arithmetic

The tool does not look up who owns an address; that needs an outside service. Everything is calculated in your browser.