When using the shipping calculator, you notice that you have to enter measurements as well as weight.
DIM weight refers to the package’s dimensional weight, which is based on its size.
To calculate the DIM weight the following calculation is used: (length x width x height) / (dimensional factor).
Please note that different carriers use different dimensional factors, therefore the final DIM weight could differ slightly between carriers for the same package. For example FedEx Express uses 169 for its dimensional factor whereas USPS uses 194.