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. It determines the size of the network and how many usable IPs are available.

How do you find the Network Address?

The network address is found by performing a bitwise AND operation between the given IP address and the subnet mask. Our calculator does this complex binary math for you instantly.

CIDR stands for Classless Inter-Domain Routing. It is a method for allocating IP addresses and IP routing. It is usually represented by a slash followed by a number (e.g., /24), indicating the number of bits used for the network portion of the address.

IT & Networking Utility

IPv4 Subnet Calculator

Perform advanced subnetting calculations instantly. Find network addresses, broadcast addresses, subnet masks, and usable host IP ranges using CIDR notation.

Network Settings

IP Address ---

Network Address ---

Subnet Mask ---

Broadcast Address ---

Usable Host Range ---

Total Usable Hosts ---

IP Class ---

What is an IP Subnet Calculator?

The IPv4 Subnet Calculator by AJAI Tech Solutions is a must-have utility for network engineers, IT administrators, and students studying for Cisco CCNA or CompTIA Network+ certifications.

Subnetting is the practice of dividing a single large network into multiple smaller, manageable, and secure sub-networks. Doing the binary math manually is tedious and prone to errors. Our tool instantly processes bitwise operations to give you flawless network blueprints.

CIDR Support

Supports Classless Inter-Domain Routing (CIDR) from /1 all the way to /32, converting prefixes to dotted-decimal subnet masks automatically.

Host Calculations

Accurately calculates the exact First and Last usable IP addresses, excluding the Network and Broadcast IPs, saving you setup time.

How to use the Subnet Calculator

Step 1: Enter a valid IPv4 address in the input field (e.g., 192.168.1.50).
Step 2: Select the CIDR routing prefix from the dropdown menu (e.g., /24 or /26).
Step 3: Click Calculate Subnet.
Step 4: Review the generated dashboard. It provides the Network Address, Broadcast Address, exact Usable Host Range, and Total Hosts available.

Frequently Asked Questions (FAQs)

In any standard IPv4 subnet, the very first IP address is reserved as the Network Address (used to identify the subnet itself), and the very last IP address is reserved as the Broadcast Address (used to send data to all devices on the subnet). Therefore, total usable hosts = $2^{(32 - CIDR)} - 2$.

Historically, IP addresses were divided into classes based on the first octet:

Class A: 1.0.0.0 to 126.255.255.255
Class B: 128.0.0.0 to 191.255.255.255
Class C: 192.0.0.0 to 223.255.255.255
Class D (Multicast): 224.0.0.0 to 239.255.255.255
Class E (Experimental): 240.0.0.0 to 255.255.255.255

This specific calculator is designed exclusively for IPv4 networks and 32-bit subnetting. IPv6 subnetting uses 128-bit hexadecimal structures and requires a different calculation algorithm.