Courier Industry have complex way of weight calculation .There are various metrics of calculation .Broadly weight is calculated by measuring actual weight or volumetric weight whichever is higher is charged. 

Volumetric weight is calculated as mentioned below :- 

1. L (cm)*B(cm)*H(cm)/5000 - Mostly followed across world

2. L(cm)*B(cm)*H(cm)/2700- Many MNCs follow this metric of calculation in India 

3. L(cm)*B(cm)*H(cm)/ 27000*8- Many Indian logistics companies follow this .