Network
IP / Subnet Calculator
Calculate a host subnet from an IP and mask, then plan bounded subnet splits.
Runs locally in your browserLoading the local workbench…
About this tool
Start with a host address plus prefix or IPv4 dotted mask, calculate its containing network, and split that network into a longer prefix. Display is bounded while counts remain exact.
Common uses
- Convert an IPv4 mask to CIDR prefix
- Find the network containing a host
- Plan smaller IPv4 or IPv6 subnets