CIDR Calculator — IPv4 & IPv6 Prefix Explorer
Parse IPv4 and IPv6 CIDR notation to understand network boundaries, address ranges, usable space, and prefix sizing. The page is built for teaching, study, and quick infrastructure checks without sending anything to a server.
Best for
CIDR practice
Input
Single or batch
Privacy
Local processing
CIDR workspace
Work through one address at a time, or paste a batch list for labs and quick revision tasks.
Batch CIDR checker
One CIDR per line. Mix IPv4 and IPv6 in the same list if you want.
Single CIDR result
Review the calculated boundary values and a few study notes about how that prefix behaves.
Frequently Asked Questions
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