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CIDR Calculator — Notation to IP Range

Expand any CIDR block into full network details

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Features

  • Range expansion
  • Host counts
  • Usable range
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This tool runs on your device — your files and inputs never go anywhere.

How to Use CIDR Calculator

Expand any CIDR block into full network details No signup, and nothing gets uploaded for most use.

  1. 1

    Enter your numbers in the input fields.

  2. 2

    Choose the calculation options or frequency.

  3. 3

    The result updates instantly as you type.

  4. 4

    Review the breakdown, chart, or schedule, and copy the answer.

Why you might like it

  • Nothing to upload — the work happens on your device.
  • Free with no signup, no watermarks, and no daily limits.
  • Works in any modern browser on any device — nothing to install.
  • Usually done in a few seconds, so it doesn't get in your way.
Try CIDR

Frequently Asked Questions

What is CIDR notation?▾

CIDR notation writes an IP address followed by a slash and the number of leading network bits, like 192.168.1.0/24. A /24 block covers 256 addresses.

How many addresses are in a CIDR block?▾

A /prefix block contains 2^(32−prefix) addresses. Usable hosts subtract the network and broadcast addresses, giving 2^(32−prefix) − 2 for prefixes below 31.

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