IPv4 Subnet Calculator - Calculate CIDR, Broadcast & Usable Hosts
Calculate network address, broadcast address, usable host IP ranges, wildcard masks, and host counts from IP and CIDR prefix.
This tool runs in your browser.
Enter an IPv4 CIDR.
How to use
- 01Enter an IPv4 address and prefix.
- 02Calculate the network locally.
FAQ
How do you calculate usable host capacity in an IPv4 subnet?
Usable host count equals 2^(32 - prefix) - 2. For a /24 block, 256 total addresses minus network and broadcast yields 254 usable hosts.
What is a wildcard mask and where is it used?
A wildcard mask is the inverse of the subnet mask (255.255.255.255 minus mask), extensively used in Cisco ACLs and OSPF network configurations.
Are subnetting computations executed locally?
Yes. Bitwise binary arithmetic runs entirely within browser memory via JavaScript, providing instantaneous offline feedback.