Network tool

IP Range to CIDR Converter

Convert an inclusive IPv4 range into the smallest exact set of CIDR blocks locally.

Example: start 192.168.1.1, end 192.168.1.50

What this result means

CIDR notation represents an aligned address block. An arbitrary range can require multiple blocks to cover it exactly without adding addresses.

How this check works

The converter chooses the largest aligned CIDR block available at each address, then repeats until it reaches the supplied end address. This produces a minimal exact decomposition.

What to do next

Use generated blocks carefully in firewall rules, allowlists, routing, or cloud ACLs; mathematical correctness does not make a range safe to allow or block.

CIDR Calculator