Subnet Calculator: Simplify Network Planning

Calculate IP ranges, subnet masks, and broadcast addresses instantly.

Managing an IP network requires precision. Whether you are dividing a large network into smaller, manageable subnets (Subnetting) or combining smaller networks into a larger one (Supernetting/CIDR), our Subnet Calculator eliminates the manual binary math. It provides a full breakdown of your network configuration, ensuring you avoid IP conflicts and maximize your available host addresses.

Understanding Subnetting Logic

On familyhealthcalc.com, we simplify the complex relationship between IP addresses and masks:

1. What is a Subnet Mask?

A subnet mask is used to determine which part of an IP address identifies the network and which part identifies the host.

• Example: In a standard home network (/24), the mask is 255.255.255.0. This means the first three numbers are the “street name” (network) and the last number is the “house number” (host).

2. CIDR Notation (Classless Inter-Domain Routing)

Instead of writing out long masks like 255.255.255.128, professionals use a slash followed by the number of “network bits.”

• /24: Provides 254 usable hosts (Standard).
• /30: Often used for point-to-point links (2 usable hosts).

3. Public vs. Private IP Classes

• Class A: 10.0.0.0 to 10.255.255.255 (Large corporate networks)
• Class B: 172.16.0.0 to 172.31.255.255 (Medium networks)
• Class C: 192.168.0.0 to 192.168.255.255 (Home and small office networks)

Why Subnetting Matters

• Security: By isolating different departments (e.g., Finance vs. Guest Wi-Fi) into different subnets, you can control traffic flow and enhance security.
• Performance: Smaller subnets reduce “broadcast traffic,” which can slow down a network if too many devices are on a single segment.
• Organization: Easily identify devices by their IP range (e.g., all printers in the 192.168.10.x range).