Classic tool
IP Subnet Calculator
Calculate network address, broadcast, host range, subnet mask and CIDR from an IPv4.
Use this IP subnet calculator to quickly find the network address, broadcast address, usable host range, subnet mask and CIDR prefix for an IPv4. It is useful for router setup, VLAN planning, firewall rules, home labs, documentation and fast network checks before you ship a change.
Enter an IPv4, change the CIDR prefix or type the subnet mask directly. The tool keeps both formats in sync and also handles the special /31 and /32 cases often used for point-to-point links and single hosts.
If you need to validate a block before assigning servers, printers, cameras or segmented environments, this page gives you the core subnet details without manual binary conversion.
Use clear inputs to get a more useful result.
How to use IP Subnet Calculator
Open the tool, fill in the fields with the data you already have and generate the result step by step. If you want to compare scenarios, change one field at a time so it is easier to understand the impact of each value.
When IP Subnet Calculator is useful
The goal here is simple: Calculate network address, broadcast, host range, subnet mask and CIDR from an IPv4. It works well for quick checks, planning, study and review before you move to a final decision or document.
What to review before using the result
Check units, labels, numbers, timing and any context that can change the meaning of the output. If the result will be used in a quote, technical task, published page or report, finish with a manual review.
Frequently asked questions
What should I prepare before using the tool?
Keep the key values, labels and units ready before filling in the fields. Cleaner inputs make the final result easier to review and compare.
Can I test different scenarios on the same page?
Yes. The safest approach is to change one field at a time, compare the outputs and note which value actually changes the final answer.
Is the result ready to use without checking it?
It is better to treat it as support. Review the output once more before using it in a quote, document, spreadsheet, technical task or published page.