IPv4 Subnet Calculator

What Is an IPv4 Subnet Calculator?

An IPv4 subnet calculator computes detailed information about an IP address and its subnet, including network class (A, B, C, D, E), address type (private, public, loopback, link-local), subnet mask in decimal, binary, and hexadecimal formats, CIDR notation, network address, broadcast address, first and last usable host addresses, and the total number of usable hosts.

Network administrators, engineers, and students use subnet calculators to plan IP address allocations, design network topologies, troubleshoot connectivity issues, and understand how subnetting works. It also supports subnetting with a new prefix length to see how a network can be divided into smaller subnets.

How to Use This Tool

1. Enter an IP address or CIDR — Type an IPv4 address with optional prefix length (e.g., 192.168.1.0/24). Use example buttons for quick testing.
2. Select a new prefix (optional) — Choose a different prefix length to see how the network can be subnetted.
3. Click Calculate — The tool computes and displays all subnet details.
4. Review the results — Check IP class, address type, subnet mask in multiple formats, network and broadcast addresses, host range, and usable host count.
5. Try different examples — Click example buttons to see calculations for common private ranges, public IPs, and special address blocks.

Frequently Asked Questions