subnetcalculator

About subnetcalculator

subnetcalculator is a free web tool for network engineers, students and anyone who needs to work out IP addressing details quickly. Enter an IPv4 or IPv6 address with a CIDR prefix and it returns the network address, subnet mask, wildcard mask, broadcast address, usable host range and total address count.

The results come with a binary view that shows where the network bits end and the host bits begin, and a draggable prefix bar that updates the numbers as you move it. This makes it easier to see why a host address like 192.168.1.10 belongs to the 192.168.1.0/24 block rather than being a separate network.

The site also includes a CIDR reference table, step-by-step subnetting guides and focused tools for IP ranges, subnet splitting, subnet merging and address conversion. Its notes on /31 and /32 handling explain the edge cases that often confuse people.