Firewall & Routing Policy Utility
IP Range to CIDR Calculator
Convert any start and end IPv4 range into the exact set of CIDR prefix blocks required for firewall access rules and routing tables.
Zero IP leakage
Resulting CIDR Blocks
Minimal covering subnets for the specified address span.
Swipe table horizontally
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Frequently Asked Questions
Clear answers to common questions about subnetting, CIDR notation, and network design.
Why do I need to convert an IP range to CIDR blocks?
Most modern networking devices, cloud firewalls (like AWS Security Groups, Google Cloud Firewalls, Cloudflare), and routing tables do not accept arbitrary start-to-end IP ranges; they require CIDR prefix blocks (e.g.,
192.168.1.0/24). This tool translates any range into the minimal exact set of CIDR subnets.