Supernetting Calculator

This IP Route Summarization Calculator is an intuitive tool designed to help network administrators, IT professionals, and students aggregate multiple IP networks into a single summarized route (supernet). This process, also known as route summarization or supernetting, reduces the size of routing tables and improves network efficiency. The tool takes multiple networks in CIDR notation as input and computes the optimal summary route, along with detailed steps, binary analysis, and efficiency metrics. For a quick reference on CIDR notation, see our IPv4 Cheat Sheet.

Understanding the Basics: Route summarization combines contiguous IP networks that share a common prefix into a larger network. This is particularly useful in hierarchical network designs to minimize routing updates and improve performance. The calculator supports IPv4 networks in CIDR format (e.g., 192.168.1.0/24) and automatically detects the longest common prefix while ensuring the summary covers all input networks without overlap issues. Learn more about CIDR and route summarization in the IETF RFC 4632.

Step-by-Step Usage:
- Prepare Your Input: List the networks you want to summarize. Each network should be in CIDR notation (IP address followed by /prefix length). Ensure the networks are contiguous and share a common prefix for optimal summarization. Example:
192.168.1.0/24
192.168.2.0/24
192.168.3.0/24
192.168.4.0/24
- Enter the Networks: Paste or type the networks into the textarea, one per line. The tool accepts multiple lines for easy input.
- Calculate the Summary: Click the "Calculate Route Summary" button. The tool will parse the input, validate each network, compute the supernet, and display results.
- View the Results: The results are divided into sections:
- Optimal Route Summary: Shows the summarized CIDR, network address, subnet mask, prefix length, efficiency percentage, and total addresses covered.
- Calculation Steps: Provides a step-by-step breakdown of how the summary was computed, including the number of networks, common prefix length, and verification details.
- Binary Analysis: Displays the binary representation of each input network and the summary route, highlighting the common prefix.
- Input Networks Analysis: Lists each input network with its network address and total addresses.
- Handle Errors: If there's an issue (e.g., invalid CIDR, non-contiguous networks), a warning modal will appear with details.
- Clear and Reset: Click "Clear All" to empty the input and hide results for a fresh start.

Best Practices:
- Use contiguous networks for best results; non-contiguous ones may result in suboptimal summaries or errors.
- Validate input: Ensure IP addresses are valid IPv4 (0-255 per octet) and prefixes are 0-32.
- Check efficiency: Aim for high efficiency (>80%) to minimize wasted addresses.
- Test with examples: Use the provided example to verify functionality.
- For large sets: The tool handles multiple networks efficiently, but very large inputs may require more computation time.
- For other subnetting needs, explore our All-in-One Subnet Calculator or our VLSM Calculator for variable-sized subnets.