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IPv4 Subnet Calculator

Calculate network, broadcast and usable host ranges

100% private. Your files and inputs never leave your device — everything runs locally in your browser.

Features

  • Network & broadcast
  • Usable hosts
  • Mask dotted
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How to Use IPv4 Subnet Calculator

Calculate network, broadcast and usable host ranges. No signup, no uploads, no watermarks.

  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 choose IPv4 Subnet Calculator?

  • No uploads — your files never leave your device.
  • Free forever with no signup, no watermarks, and no limits.
  • Works on any device with a modern browser — no installs.
  • Fast, private, and built for getting the job done in seconds.
Try Subnet for free

Frequently Asked Questions

What is a subnet mask?

A subnet mask marks which bits of an IPv4 address identify the network and which identify the host. A /24 mask is 255.255.255.0 and leaves 8 host bits.

Why are the first and last addresses special?

The network address (all host bits zero) identifies the subnet itself, and the broadcast address (all host bits one) reaches every host on it. Neither is usable as a host.