Guide To Subnet Mask (Subnetting) & IP Subnet Calculator

An IP address is used to identify a particular device within a network and the host. Subnetting and IP addresses are combined to develop multiple logical addresses within a single network.

A network can be divided into different classes, each having a specific role and significance in computer networks. Human beings identify themselves by their names every day. Routers and switches use a subnet mask and IP address to identify their neighboring devices and networks. 

So, without wasting time. Let’s get into it to dig deep about the subnet mask and IP subnet calculator. To understand subnet masks, we need to understand IP addresses first.

Understand IP Addressing 

Logic addressing is a widespread phenomenon that operates at Layer 3 of the OSI reference model and is most commonly used with network components such as routers and switches.

Network hosts are uniquely identified by their IP addresses, which are 32-bit logical addresses. It can be a computer, a mobile phone, or a tablet. A 32-bit binary IP address has two parts: The Network address and the Host address.

Each octet has 8 bits, so it has four octets in total. A dot separates this octet from its decimal representation and is converted to decimal. In this way, it is represented as a dotted-decimal. In binary, an octet ranges from 00000000 to 11111111, while in decimal, it ranges from 0 to 255.

Here is an example of an IP address format: (in decimal)

11000000.10101000.00000001.01000000 (in binary).

The binary one is hard to remember; thus, the dotted decimal format is commonly used worldwide to show logical addressing.

What is a Subnet Calculator?

In networking and information technology, the Subnet Calculator is a handy tool. As it’s name shows, it’s pretty self-explanatory what it does. Subnets can be calculated with the help of this tool. 

A Subnet Calculator works by taking a range of IP addresses or CIDR notations and calculating/generating a list of subnets. 

We’ll look at subnetting if you need to familiarize yourself with it.


It is possible to create subnetworks or logical networks within a single network of a particular network by subnetting it. Extensive networks cannot be developed without subnetting.

Each link in a comprehensive networking system must have a unique IP address, and so must every device participating in the network.

A subnetting technique works by dividing a large network into smaller subnetworks to enable interconnection between nodes located at different locations within that network class (A, B or C).

There would be a specific IP address and subnet mask linked with each node on the network. For each network with which a switch, router, or gateway interconnects, it has a unique Network ID and subnet mask.

What does the Subnet Calculator do?

Subnet Calculator generates a list of subnets based on a range of IP addresses (or CIDR Notations). 

With this calculator, you can easily divide your network into subnets. Calculating, dividing, or converting decimals to binary is not needed. It is a handy tool for someone who deals with subnets daily.

There are many options to help you customize the list of subnets. Your network can have any size of subnet and any number of subnets you want. It is also possible to customize the size of each subnet (since all subnets can be different).

What are the Classes of Networks?

Class A, Class B, Class C, Class D, and Class E are the five classes of subnetworks. Each class corresponds to a range of IP addresses. Different networks most commonly use classes A, B, and C.

An IP address’s subnet class can be distinguished by the number of bits it dedicates to a network and by how many bits it dedicates to hosts. A subnet mask is assigned to each of them by default. In an address, the number in the first octet identifies a class.

  • Class A: First Octet Value 0-127
  • Class B: First Octet Value 128-191
  • Class C: First Octet Value 192-223
  • Class D: First Octet Value 224-239
  • Class E: First Octet Value 240-255

What is a Class A IP Address? 

In a Class A IP address, 8 bits are reserved for the network, and 24 bits are reserved for the hosts. An IP address for this server ranges from 0 to 127. Generally, a subnet mask of is used for Class A IP addresses. As a result, large networks are the finest applications for Class A IP addresses.

Class B IP addresses, which reserve 14 bits for a network and just 18 bits for hosts, are better suited to serving smaller networks than Class A IP addresses. These have network addresses between 128 and 191.

As a result, serves as the class B default subnet mask. Additionally, very small networks frequently receive Class C IP addresses. Their default subnet mask is, and their IP addresses range from 192 to 233.

What is the use of Class D and Class E IP Addresses?

Most IP addresses assigned to Class D and Class E are used for experimental purposes only. In multicasting applications, Class D IP addresses are almost exclusively reserved. In multicasting, multiple senders communicate with multiple receivers over a computer network. 

Class D cannot be part of normal networking operations, unlike Classes A, B, and C. This is due to the absence of host bits within the address space of Class D.

There is a common belief that Class E was created for future use, research, and development. The actual use of these IP addresses has never been developed, even though they are reserved. Therefore, this class is generally ignored by most network implementations. 

Sometimes Class E is considered illegal or undefined. It is possible to use IP address as a broadcast address (a network address that connects devices to a network with multiple access points).


In the end, we hope all your doubts regarding subnetting and the subnet calculator have been cleared. Moreover, we have discussed different classes of networks and their use. But, if you still have any doubts regarding these topics, feel free to ask us in the comment section below.

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