A subnet number is a specific part of a subnet address in an IP address that identifies one among several subnets as the recipient or originator of a data packet.
It helps browsers to accurately use the Internet to deliver messages to specific parts of a party’s full network.
Formula to calculate subnet number.
![Calculate Subnet Number.](https://www.learntocalculate.com/wp-content/uploads/2021/04/subnet-number.png)
Example:
If the number of subnet bits is 7, calculate the subnet number.
![Calculate Subnet Number.](https://www.learntocalculate.com/wp-content/uploads/2021/04/subnet-number-2.png)
Therefore, your subnet number is 128.