CIDR merger

Join a list of IPv4 subnets, addresses and ranges into the smallest set of CIDR blocks.

Subnets, addresses and ranges10.10.0.0/24 10.10.1.0/24 10.10.2.0/23 10.10.4.7 192.168.0.0-192.168.0.127 192.168.0.128/25

Merged list

Runs in your browser. Nothing you type is sent to the server.

About this tool

Paste IPv4 subnets such as 10.1.0.0/24, single addresses such as 10.1.1.5 or ranges such as 10.1.2.0-10.1.2.255, one per line or separated by commas. Overlapping and neighbouring entries are joined, and the result is the shortest list of CIDR blocks that covers exactly the same addresses, with none added. Use it to tidy firewall rule sets, route tables and allow lists. It handles IPv4 only.