IPv4 Subnet Calculator
The complete tool for all your IPv4 subnetting needs. Calculate subnet details, including network address, usable IPs, broadcast address, and more.
Subnetting is the process of dividing a single, large computer network into smaller, more manageable subnetworks, or "subnets." It's a fundamental practice in IP networking that provides numerous benefits for network organization, security, and performance.
Why Do We Subnet?
- Improved Performance: By segmenting a network, you reduce broadcast traffic. Broadcasts are contained within their own subnet, preventing them from consuming bandwidth across the entire network.
- Enhanced Security: Subnets allow you to implement security policies between networks. You can control traffic flow with Access Control Lists (ACLs) on a router, for example, allowing a "Sales" subnet to access the internet but not the "Engineering" subnet's servers.
- Simplified Management: Smaller networks are easier to manage and troubleshoot. Identifying and isolating network problems becomes a much faster process.
How It Works
Subnetting involves "borrowing" bits from the host portion of an IP address and using them to create subnet identifiers. The subnet mask is what determines which part of the IP address is the network portion and which is the host portion. Our calculator automates this complex bitwise math for you. For more advanced scenarios, try our VLSM Calculator to create subnets of varying sizes.
For more detailed information on network classes and private ranges, refer to RFC 1918.