Subnet Tools Tools
CIDR, netmask, VLSM, and IP range calculators
Subnet Calculator
Calculate network, broadcast, mask, and host range from IP and prefix
CIDR Calculator
Convert between CIDR notation, subnet mask, and IP range
VLSM Calculator
Variable-length subnetting for multiple host requirements
IPv6 Subnet Calculator
Calculate IPv6 subnet prefix, groups, and address count
Wildcard Mask Calculator
Compute wildcard mask from subnet mask or CIDR prefix
Subnet Mask Converter
Convert dotted-decimal mask to CIDR prefix and back
IP Address Planner
Plan sequential subnet allocations from a parent block
Network Address Calculator
Find the network address for any IP and subnet mask
Broadcast Address Calculator
Find the broadcast address for any IP and prefix
Usable Host Calculator
Calculate usable host count and range for a subnet
Subnet Split Calculator
Split a CIDR block into equal smaller subnets
Subnet Merge Calculator
Merge adjacent equal-size subnets into one block
CIDR Aggregation Tool
Aggregate multiple CIDR blocks into summary routes
CIDR Overlap Checker
Detect overlapping IP address ranges and CIDR blocks
IP Allocation Table Generator
Generate a subnet allocation table from a base network
VLAN Subnet Mapping Tool
Map VLAN IDs to CIDR subnets in a network design
DHCP Scope Calculator
Calculate DHCP pool range excluding network and broadcast
DHCP Exclusion Calculator
Generate DHCP exclusion ranges from reserved IP list
Supernet Calculator
Combine contiguous subnets into a supernet summary
Route Summarization Tool
Summarize IP routes into optimal CIDR advertisements
ACL Wildcard Generator
Generate Cisco ACL wildcard masks from IP and subnet
Cisco Subnet Helper
Generate Cisco IOS subnet and interface configuration
FortiGate Address Object Generator
Generate FortiGate address and addrgrp CLI commands
MikroTik Address List Generator
Generate MikroTik firewall address-list entries
Subnet Cheat Sheet Generator
Generate a printable CIDR and subnet mask reference table