Subnet Calculator

Enter an IP address with CIDR prefix to calculate subnet details.

How to Use Subnet Calculator

  1. Enter your values in the input fields.
  2. Results update automatically as you type.
  3. Use the Copy button to save your results.

All processing happens locally in your browser. Your data is never uploaded to any server.

Frequently Asked Questions

Is Subnet Calculator free to use?

Yes, completely free. No signup, no limits. All processing happens in your browser — your data never leaves your device.

Does Subnet Calculator work on mobile?

Yes, it works on all devices including phones and tablets. The interface is fully responsive.

Is my data safe?

Absolutely. Everything runs locally in your browser using JavaScript. No data is uploaded to any server.

How accurate are the calculations?

Calculations use standard JavaScript floating-point math, accurate to 15 significant digits.