Is shipping cost calculated by package weight or size?

Many variables affect the cost of shipping, be it international or local. The shipping cost differs from company to company, and of course, the faster the service, the more the cost. Most shipping companies use the physical dimension method called dimensional weight (DIM weight). It considers the size of the package to determine the shipping cost.

Some companies use the actual weight to determine the price. However, many shipping carriers calculate the cost based on whichever is greater; the physical weight or DIM.