Packetrove

IP ADDRESS TOOLS

Smallest Covering CIDR

Combine IPv4 or IPv6 addresses and ranges into the smallest single CIDR that covers them all.

Calculated in your browser · No API request

Your addresses

IPv4 / IPv6

One entry per line. Use one address family per calculation. Up to 1,000 entries.

0 entries

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Coverage result

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Enter your addresses to see their covering CIDR, address range, and any extra coverage.

Understand the coverage

The longest possible prefix gives the smallest single covering range. That range can include addresses outside your original entries. Overlapping entries are counted once, and CIDRs with host bits are normalized.

Counts include every address in a range, including network and broadcast addresses. Review additional coverage before using a result in an allowlist or blocklist.

CIDR calculation examples

Enter individual addresses or CIDR ranges, with up to 1,000 entries. IPv4 and IPv6 cannot be mixed in one calculation. IPv6 address counts remain exact, even for very large ranges.

Exact IPv4 coverage

203.0.113.0/25
203.0.113.128/25

203.0.113.0/24 covers 256 addresses and adds 0.

IPv4 with extra coverage

203.0.113.1
203.0.113.2
203.0.113.6

203.0.113.0/29 covers 8 addresses and adds 5.

Exact IPv6 coverage

2001:db8::/64
2001:db8:0:1::/64

2001:db8::/63 covers 36,893,488,147,419,103,232 addresses and adds 0.