# FREE Online IP Subnet Calculator with Custom Mask

This is a simple and very powerful tool for calculating IP, subnet IP address, subnet mask, wildcard mask, and IP class types, and many other details.

This FREE tool can be used for learning and studying networking. Give IP address and subnet mask as input and you will get all the IP address details.

Here is the detail about each field used in the IP subnet calculator.

The IP (Internet Protocol) address is the address assigned to the device (computer) by which other devices identify it.

This IP address is a part of the network layer (3rd layer in the OSI layer model architecture).

It is 32 bits address and split into four-octave.

Syntax:

`x.x.x.x`

where x is in the range of 0 (00000000) to 255 (11111111).

By default, IP address is considered as `IPv4` IP address. There is also an `IPv6` IP address. You can read the difference between IPv4 and IPv6 addressing.

#### 2. IP Class Type

All the IP addresses are classified into five types called class A, class B, class C, class D, and class E. This classification is based on the starting bits of the first octave

#### 3. Subnetting

For the sake of simplicity, there is a provision to divide the network into multiple subnets. This process is called as subnetting.

This is a simple definition. There are multiple benefits of subnetting. Read it in detail.

Some of the starting bits in the 32 bits IP address are used to identify the network. The number of these bits is called as netmask (says `n`).

Remaining bits `(h = 32-n)` are used to identify the host in the network.

#### 5. Host/Net

It is the number of hosts (connected devices) present in the network or subnet.

It is calculated as `2^h-2`.

• `2^h` is the number of unique IP addresses that can be formed by `h` number of bits.
• The IP address with all host bits as zeros and all host bits as ones are special IP addresses. These special IP addresses are not assigned to any host in the network. So, we have subtracted two from the actual number.

6. Example

```n = 23 (netmask)
h = 32-n = 32-23 = 9 (host bits)
Number of host/net = 2^9 - 2 = 512 - 2 = 500```