VLSM Calculator (Variable Length Subnet Mask) Enter a primary network and required usable hosts for each VLAN. The calculator will automatically allocate subnet sizes, CIDR, and masks. Primary Network Base Network (CIDR) VLAN RequirementsVLAN Name / IDRequired Usable HostsAction Add VLAN Calculate VLSM VLSM Allocation ResultVLANRequired HostsCIDRSubnet MaskNetworkUsable RangeBroadcastWasteSubnet Allocation VisualizerTotal IPs0Used IPs0Wasted IPs0Remaining IPs0 Download PDF Report