Calculate IPv4 network partitions and broadcast boundaries with our free Subnet Calculator. Compute Network ID addresses, Broadcast targets, Wildcard netmasks, and usable host allocations with 100% offline privacy.
Input an IPv4 address (e.g. 192.168.1.0) into the input field.
Choose a subnet mask (/24, /16, /8, etc.) from the dropdown menu.
Examine Network ID, Broadcast Target, and Wildcard Mask outputs instantly.
Uses 32-bit unsigned bitwise operations (ip & mask and net | wildcard) for fast subnet partitioning.
Calculates bitwise inverse netmasks (~mask) needed for Cisco ACLs and router filtering policies.
All calculations execute locally in your browser DOM memory. No internal network topologies are sent to servers.
An IPv4 address consists of 32 bits divided into four 8-bit octets. Subnetting uses a subnet mask to split the address space into a Network ID (network portion) and a Host ID (device portion).
The Network ID is computed by performing a bitwise AND operation between the IP address and the subnet mask (Net = IP & Mask). The Broadcast address sets all host bits to 1 via bitwise OR (Broadcast = Net | ~Mask).
The Wildcard mask is the bitwise NOT of the subnet mask (Wildcard = ~Mask). For example, a 255.255.255.0 mask (/24) yields a wildcard mask of 0.0.0.255.