CIDR converter

Turn a start–end address range into the smallest set of CIDR blocks that covers it exactly, or expand a CIDR block back into its range. The same routine our registry importer uses.

Range → CIDR

Start address

End address

3 blocks · 131 addresses

cidr: 192.0.2.0/25
cidr: 192.0.2.128/31
cidr: 192.0.2.130/32

CIDR → range

CIDR block

first: 198.51.100.0
last: 198.51.103.255
range: 198.51.100.0 - 198.51.103.255
addresses: 1,024