What is a subnet mask?

A subnet mask is a 32-bit number that masks an IP address and divides the IP address into network address and host address. For example, 255.255.255.0 is a common subnet mask.

How do I calculate usable IP addresses?

For a /24 subnet, total IPs = 256. Subtract 2 (network and broadcast) = 254 usable hosts. Use our calculator for any CIDR.

Subnet Calculator – Calculate IP Subnets, CIDR & Network Ranges

Calculate IP Subnets Easily

Subnetting divides a large network into smaller, more manageable segments. It improves performance, enhances security, and simplifies troubleshooting. Our calculator supports CIDR notation (e.g., /24) and provides all essential subnet parameters.

CIDR & Subnet Mask Explained

CIDR (Classless Inter-Domain Routing) replaced the old classful system. The /24 notation means the first 24 bits are the network portion, leaving 8 bits for hosts (254 usable IPs). Understanding CIDR is crucial for efficient IP address management.

Network Planning Made Simple

Use this tool to plan IP allocations for VLANs, VPNs, and branch offices. Combine with Infusionicsoft NMS to automatically discover devices and monitor subnet health in real time.