IP Subnet Calculator
IPv4 subnet mask and hosts (CIDR).
Frequently asked questions
What does the IP Subnet Calculator do?
IPv4 subnet mask and hosts (CIDR). Enter your values and get an instant estimate in your browser — free, with no signup.
Is the IP Subnet Calculator free to use?
Yes. OpenCalcy calculators are free to use, work on mobile, and keep favorites privately in your browser.