CIDR aggregator — merge & summarize subnet lists (local)
Paste one CIDR per line to normalize network boundaries, merge overlapping or adjacent blocks, and copy a minimal summarized list for firewall rules and route tables.
Frequently asked questions
No. CIDR parsing and aggregation run entirely in this tab—lists are not uploaded. Nothing is sent to LocalTools servers for processing.
Yes. Overlapping and directly adjacent CIDR blocks collapse into the smallest covering set, then decompose into minimal prefix blocks.
CIDR notation expects the network address. Use `192.168.1.0/24`, not `192.168.1.10/24`. The Subnet Calculator can derive the network for a host IP.