The difference between the actual weight of an airfreight shipment and the dimensional weight that is often used as the chargeable weight is very misunderstood by most exhibitors. Today I want to provide a basic understanding as to why there are two different weight categories when you ship air freight. The airfreight company will tell you that the actual weight of a shipment will be charged unless the dimensional weight (or DIM weight) is greater. So what does that mean?
Ok – you have a shipment going from, let’s say Washington DC to Las Vegas. The shipment is only one average size pallet. It is not enough to send on a tractor /trailer so you opt for airfreight. You or your exhibit company consolidates the boxes and portable exhibit cases onto a pallet and stretch wrap the pieces together. The three dimensions of the pallet when finished are 40”wide x 48” deep x 37”tall. The actual weight of the pallet is 285lbs. You later get the bill from the airfreight company and instead of being charged the actual weight of 285lbs. you are charged for 336 lbs. of “dimensional weight”. The dimensional weight was greater so that is the weight used to calculate the price.
So let’s understand two basic principles.
- You could ship a box of feathers which weighs very little or you could ship the same size box of bricks which weighs a lot. Either box still takes up the same amount of space on a plane so the airline will charge a minimum weight fee for that space. For the bricks you would expect the actual weight to be greater. On the contrary, the feathers will be charged a minimum dimensional weight instead of using their actual weight.
- The dimensional weight calculation. Airfreight companies use a minimum density calculation to determine the charge for the box. So what is this theoretical calculation? I will give you the one most commonly used for domestic flights in the US.
It is length x width x depth divided by 194. The math comes out to a minimum dimensional weight of 8.9 lbs. per cubic foot.
Let’s use the example I talked about earlier. The pallet to Vegas was 40” x 48” x 37” and weighed 285lb. Using the dimensional weight formula we would multiply 40 x 48 x 37 and then divide the total by 194 to get 366 lbs. Because the dimensional weight of the pallet is higher than the actual weight, the dimensional weight will become the “chargeable weight” on your airfreight bill.
Next week we will look ways to control air freight costs.