IPv4 Range to CIDR Expander

Made for the task at hand.

Turn firewall and address-plan ranges into aligned CIDR notation. The converter repeatedly selects the largest permitted block, producing a minimal set that covers every address from start through end and nothing outside that interval.

How to use

1. Enter the first IPv4 address in the inclusive range.
2. Enter the final IPv4 address, which must not be lower.
3. Copy the exact CIDR list and address/block totals.