Subnet Split
Split an original network into multiple subnets
How to use
About this tool
Splits an original network (CIDR notation) into multiple subnets. Supports three split methods (subnet count, required host count, new prefix length) and calculates and displays each subnet's network address, host range, broadcast address, and host count in real time. All calculations are done in the browser.
How to use
Enter the original network in CIDR notation (e.g., 192.168.1.0/24). Select a split method (specify by subnet count, specify by host count, or specify by new prefix length). Enter the parameter for the selected method (subnet count, host count, or prefix length). Results are displayed in a table in real time as you type. You can copy the results or download them as CSV.
Options
Original network: CIDR notation (e.g., 192.168.1.0/24). Split method: Specify by subnet count (enter subnet count), specify by host count (enter hosts per subnet), or specify by new prefix length (enter new prefix length). Results: Each subnet's No, network (CIDR notation), host range, broadcast, and host count are displayed in a table.
Use cases
β’ Subnet splitting for network design β’ Preparing for VLSM (Variable Length Subnet Mask) design (creating multiple subnets of the same size) β’ Network segment design (determining subnet size from required hosts per segment) β’ Router and switch configuration (checking network addresses and host ranges for each subnet) β’ Network management (creating and documenting subnet lists)
How it works
Subnet splitting calculates each subnet's size and network address from the original network's prefix length and the new prefix length. When calculating new prefix length from subnet count: newPrefixLength = originalPrefixLength + Math.ceil(Math.log2(subnetCount)). When calculating from host count: newPrefixLength = 32 - Math.ceil(Math.log2(hostCount + 2)) (accounting for network and broadcast addresses). Each subnet's network address is calculated as original network address + (subnet number Γ subnet size). All calculations are implemented with JavaScript bitwise operations and complete instantly in the browser.
Privacy and data
All calculations are done in the browser; no network information is sent to any server.