CIDR Route Summarization & Supernet Calculator
Merge contiguous or overlapping IPv4 CIDR blocks, single IPs, and start–end IP ranges into the minimal exact CIDR list for cloud firewall quotas—or compute a single BGP/OSPF summary supernet.
Aggregation Summary & Quota Impact
Optimized CIDR Prefix Table (click any cell to copy)
| Aggregated CIDR | Subnet Mask | Wildcard Mask | Address Span | Total IPs |
|---|
Ready-to-Paste Router & Cloud Firewall Snippets
Exact CIDR Aggregation vs. BGP Supernet Route Summarization
Route summarization (also known as supernetting or CIDR aggregation) collapses multiple adjacent or overlapping IP prefixes into shorter prefix lengths. In core routers and data-center switches, summarizing routes shrinks Forwarding Information Base (FIB) and expensive TCAM table entries while containing routing protocol churn when individual downstream links flap.
In cloud engineering and security operations, Exact Merge mode is essential whenever allowlists enforce hard entry quotas—for example, AWS VPC Security Groups default to 60 inbound rules per group, and WAF IP sets charge per rule evaluation. Exact binary interval decomposition deduplicates nested subnets (such as a stray /28 inside an existing /24), converts arbitrary start–end IP ranges into valid CIDR boundaries, and merges sibling blocks (such as four contiguous /24 networks into a single /22) while introducing zero unauthorized IP addresses.
By contrast, Single Supernet mode computes the tightest single umbrella prefix covering every input network for BGP aggregate-address or OSPF area range statements. Whenever your input prefixes contain unallocated gaps, a single umbrella summary advertises extra IP space—always pair non-exact BGP summaries with a local Null0 discard route to prevent routing loops for unused sub-blocks. Need to split a parent block instead? Try our VLSM Subnet Splitter.