CIDR Subnet Calculator
Calculate IPv4 networks, broadcasts, masks, host ranges, membership, and subnet splits.
CIDR input
Enter an IP/prefix such as 10.0.0.0/8; all calculations run locally in the browser.
IP membership check
Enter an IP to check whether it belongs to the network above.
About CIDR Subnet Calculator
Enter an IPv4 CIDR to inspect its network, mask, address range, and subnet divisions.
Are network and broadcast addresses always excluded?
The tool handles /31 point-to-point links and /32 host routes separately. Confirm that your network equipment and intended use support the chosen subnet.