CIDR Summarize / Aggregate
Merge or dedupe a CIDR list. Fail-fast on the first invalid line. Same family only.
Developer notes
• One CIDR per line; # comments skipped. • Fail-fast with line number. • No mixed family. • Never invents gap coverage.
Options
When teams pick this route
• Shrink an allowlist. • Dedupe an ACL export.
Worked examples
Nested merge
Before
After
Adjacent /25 → /24
Before
After
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.
More networking tools in this cluster
Looking for converters, encoders, formatters, and minifiers in one place? Developer tools hub Open the curated developer tools catalogue.