Network / IP

CIDR Checker

Check whether an IPv4 address belongs to one or more CIDR ranges.

What is CIDR Checker for?

CIDR Checker determines whether an IP belongs to a specific network range. It is useful for allowlists, blocklists, firewall rules, and provider IP lists.

Recommended workflow

  1. Enter the IPv4 address you want to check.
  2. Paste one or more CIDR ranges to match against.
  3. See which range matches and use the result for network rules.

How this tool works

Network tools normalize IP, CIDR, host, or URL input, then calculate ranges or inspect live response metadata. They are useful for checking routing assumptions, allowlists, response headers, redirects, and public network ownership.

Part of this tool group

Open nearby tools in the same group to cross-check, inspect deeper, or complete a small workflow.

Open Network / IP hub

Frequently asked questions

Does CIDR Checker support IPv6?

This tool focuses on IPv4; use the IPv6-specific formatter or checker for IPv6 workflows.

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