IP Range to CIDR — Exact Cover
Convert an inclusive start–end range into minimal exact CIDRs (IPv4 or IPv6).
Developer notes
• start ≤ end required. • Exact cover — no overshoot. • 64 KiB limit.
Options
When teams pick this route
• Turn a firewall range into a CIDR list. • Check a non-aligned range.
Worked examples
Aligned /24
Before
After
Non-aligned
Before
After
Related networking tools
To aggregate CIDRs: cidr-summarize. Hub: networking tools.
Range → CIDR FAQ
Exact cover
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.