Variable Length Subnet Mask (VLSM) is a technique used in IP address allocation. It allows network administrators to use different subnet masks for different subnets in a network, making it more efficient by utilizing IP addresses according to the need of each subnet. VLSM helps to reduce waste of IP addresses by allocating a subnet mask that fits each subnet's size.

With VLSM, a network can have subnets of varying sizes, depending on the requirements of each department or segment of the network. This is particularly useful for large networks where different departments or sections might require different numbers of IP addresses.

This tool helps you calculate VLSM subnets and visualize the network details based on your input parameters.