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CIDR Overlap Checker
Compare two same-family CIDRs and report containment or their exact intersection.
First CIDR, Second CIDR
cidr-overlap-checker.json
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Enter the displayed inputs, using the example values as a starting point. JSON inputs must use the documented shape.
- Choose Calculate result, inspect the complete report and download its JSON file.
- Change inputs and run again, or Reset to restore the examples and clear working output.
Examples
First CIDR: 192.0.2.0/24
Second CIDR: 192.0.2.128/25
Limitations
- IPv4 or hexadecimal IPv6, same family. Host bits are normalized. No address enumeration.
- At most 100,000 UTF-16 units per text field and 400,000 UTF-8 bytes combined input; 4 MiB output and a 30-second local worker. Valid Unicode only. Tool-specific limits may be tighter.
- Decimal engineering calculations use finite JavaScript arithmetic. Structured record operations preserve exact JSON numeric tokens. Reports are local calculations or bounded format inspections, not a claim of external validity.
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