CIDR Summarize / Aggregate

Merge or dedupe a CIDR list. Fail-fast on the first invalid line. Same family only.

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CIDR summarize
mergeOverlaps merges overlaps and adjacent blocks; otherwise exact-string dedupe only.

Developer notes

• One CIDR per line; # comments skipped. • Fail-fast with line number. • No mixed family. • Never invents gap coverage.

Options

Merge overlaps
true = minimal covering merge; false = exact-string dedupe without adjacent merge.
Output sort
ascending = lexical CIDR sort; none = compute / first-occurrence order.

When teams pick this route

• Shrink an allowlist. • Dedupe an ACL export.

Worked examples

Nested merge

Before

10.0.0.0/8 10.1.0.0/16

After

10.0.0.0/8

Adjacent /25 → /24

Before

10.0.0.0/25 10.0.0.128/25

After

10.0.0.0/24

Related networking tools

For a start–end range: ip-range-to-cidr. Hub: networking tools.

CIDR summarize FAQ

Merge & dedupe

When should I use the number-base converter instead?

To convert an integer between bases 2–36 (hex of a number, binary of a value), use number-base-converter. Networking tools compute subnets and CIDRs — not general base conversion.

Are IP addresses uploaded?

No. All math runs locally in your browser. Nothing is uploaded to FastMinify.

What is the size limit?

64 KiB (UTF-8) for the combined input fields of each tool.

Networking / IP

CIDR, subnets, and IPv4/IPv6 helpers — in your browser.

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