IP in Subnet — Contains / Overlap
Check whether an IP is inside a CIDR, or whether two CIDRs overlap.
Developer notes
• Same family required. • Forced family → error on mismatch. • 64 KiB limit.
Options
When teams pick this route
• Smoke-test an ACL rule. • Check whether two prefixes intersect.
Worked examples
Contains
Before
After
Overlap
Before
After
Related networking tools
Calculator: subnet-calculator. Hub: networking tools.
IP in subnet FAQ
Contains & overlap
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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