How to Calculate a Subnet Mask Quickly

Essential for network engineers and students learning TCP/IP. No formulas to memorize — just enter and get results.

  1. Open Subnet Calculator
  2. Enter an IP address and CIDR (e.g., 192.168.1.0/24)
  3. Click Calculate
  4. View network address, broadcast, and usable host range
Open Subnet Calculator

Frequently Asked Questions

Is this free?

Pay what you want. Most users pay $2. No subscriptions.

Do I need to install software?

No. Everything runs in your browser. No downloads, no installs.

Is my data safe?

Yes. All uploads are auto-deleted after 1 hour.