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CIDR Calculator

Calculate IPv4 and IPv6 CIDR networks, ranges, masks, and host counts.

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IP / CIDR

About

Calculate normalized IPv4 or IPv6 network boundaries with exact integer arithmetic, including large IPv6 address counts.

Key Features

  • IPv4 and IPv6
  • Network and last-address range

How to use

  1. 1Enter an address with a prefix length.
  2. 2Calculate and copy the required field.

Example

Input

192.168.1.42/24
2001:db8::1/64

Output

192.168.1.0/24 — 192.168.1.255
2001:db8::/64 — 2001:db8::ffff:ffff:ffff:ffff

Limitations

  • Input is limited to 2,000,000 characters to keep the browser responsive.
  • Usable-host counts follow the traditional IPv4 network/broadcast convention; point-to-point exceptions are not inferred.
  • All input is processed locally in your browser and is never uploaded to ToolHub.

Standards and references

Last reviewed:

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