How to Calculate Air Freight


June 07, 2013


The Complex Topic of Air Freight Calculations and Dimensional Weight

If you need to calculate freight, especially air freight, you might find it’s a little bit more complex than it appears at first. That’s because you need to calculate freight shipping using something called volumetric weight, dimensional weight, or DIM weight. This type of weight is not necessarily equal to the actual weight of the package. Instead, it uses the length, width, and height of the package to get the dimensions, which are modified by a “shipping factor.”

When you calculate freight, you need to apply an appropriate shipping factor. The shipping factor used depends on the origin point of the freight shipment and other factors. To calculate freight shipment accurately, you select a factor in either cubic inches per pound or cubic centimeters per kilogram, depending on the type of measurements used in the region.

Regardless of how the shipping factor is expressed, it represents the inverse of the package density. What does this mean? Well, dimensional weight provides a way to calculate a shipment in terms of the minimum parcel or package density that a given carrier will accept.

That means dimensional weight is used when the minimum density of the shipping factor is larger than the parcel’s actual density. If the parcel density was higher, then the basis of the charges would be the conventional measured weight, not the dimensional weight.

Why Do You Need to Understand How to Calculate Dimensional Weight?

Freight carriers are at an advantage when it comes time to calculate freight, because they are empowered to calculate freight shipping in the way that most benefits them – charging you for the actual weight of the shipment or the weight of the package at a given set of dimensions and minimum density. This theoretical minimum density serves as a “break-even” so that carriers won’t lose shipping space by taking up a large dimensional area with a light shipment.

The reason it’s important to be able to calculate dimensional weight is so that you, as the client, can “double check” the calculations done by the carrier. As noted above, the calculations are intended to provide profit potential for carriers in situations where their margin might already be slim. Ordinary human error can lead to situations where the volumetric weight of a shipment is miscalculated, creating the potential for an unjustified shipping price.

An Example of How Dimensional Weight is Calculated in Air Freight

A precise measurement of dimensional weight is not always used – sometimes, air carriers will simply use the longest dimensions to make the calculation. However, there is a formal and somewhat longer way to go about it, which yields a more exact result.

The basic formula for dimensional weight is:

(L x W x H) / DF

This is true where ‘L’ is length, ‘W’ width, and ‘H’ height. ‘DF’ is the dimensional factor.

The appropriate dimensional factor is up to the shipper. Many major vendors have their own dimensional factor used for all shipments within their network. Some countries and regions suggest certain dimensional factors for shipments taking place in their area of influence. The proper dimensional factor can also be influenced by customs rules.

Once you have the dimensional weight, consult with the carrier to find out the schedule of fees for a given weight. The final price will depend on factors such as the distance the shipment travels, customs costs, and other elements that cannot be estimated without specific information.

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