CIDR Calculator
Free CIDR calculator: parse, merge and summarize IPv4 CIDR blocks, with address counts and ranges.
What does CIDR summarization do?
It merges adjacent and overlapping blocks into the smallest possible set of CIDR prefixes, so address planning only needs to advertise a handful of routes.
Why is the total smaller than the sum of the inputs?
Overlapping blocks count only once — every address in the union is unique.
What does the capacity column mean?
The number of IPv4 addresses contained in the summarized block, including network and broadcast addresses.
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