Split an IPv4 CIDR block into smaller subnets with a longer prefix length.
Subnets
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Addresses each
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Parent
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Enter the example value or paste your own input, choose the mode when one is available, and read the first result card for the direct answer. The output area gives a copyable block for code reviews, documentation, API tests, classwork or troubleshooting notes.
What the result means
The splitter increments through the parent range in blocks sized by the requested new prefix.
What is not included
The preview is limited to the first 256 subnets. Use network planning software for very large allocations.
Privacy note
The calculation runs in your browser. Avoid pasting production secrets, credentials, private keys, customer data or regulated personal data unless your own policy allows browser-based tools.