Visual Subnet Calculator

This tool acts as an interactive canvas. Instead of blindly calculating numbers, it allows you to dynamically break down a large chunk of IP space into perfectly sized, non-overlapping networks.

1. Step 1: Set Your Base Network. Define your starting parent block using the inputs at the top. The table will generate a single row representing that entire network.
2. Step 2: Splitting Subnets. Click the Split block (green) on any row in the hierarchy column. The mathematical engine will instantly borrow one network bit, dividing that specific subnet perfectly in half.
3. Step 3: Joining Subnets. You can reverse a split by clicking the Join block (blue). The tool will merge them back into their larger parent subnet, provided neither branch is further divided.
4. Step 4: Customize & Export. Use the "Show Columns" toggles to hide data you don't need, then click the Copy or Download CSV buttons to export your completed VLSM map directly to your clipboard or spreadsheet.

Visual subnetting is highly useful for real-world IT environments. Here are the most common scenarios where this tool saves time:

• Office Network Planning: Easily carve up an office network to separate different departments (like HR, IT, and Guest WiFi) into their own secure routing blocks.
• Router & Firewall Configuration: Generate the exact IP ranges, network masks, and wildcard masks needed to write accurate routing rules and Access Control Lists (ACLs).
• IT Certification Exams: Practice and visually verify your subnetting math for the CCNA, Network+, or other professional networking exams.