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IP Range to CIDR

Convert a start–end IP range to the smallest list of CIDR blocks, and back.

About IP Range to CIDR

Turn a range such as 10.0.0.5 – 10.0.1.20 into the minimal set of CIDR blocks for firewall rules and access lists, or expand CIDR blocks into their first and last address.

How to use

  1. Type an IP address, host name, domain or coordinates – or use the values filled in for you.
  2. Press Enter or the button – results appear instantly, and the page link keeps your query for sharing.
  3. Click any value to copy it; tables can be sorted and exported as CSV or JSON.

WhereNex does not store the addresses, names or positions you look up. IP locations come from our own copy of the DB-IP database (CC BY 4.0) and are approximate.

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