Calculate Shipping Cost for Air Freight: The Impact of the DIM Factor

To calculate shipping costs for air freight, consider a shipment of 50 identical cartons whose dimensions are 20in x 20in x 20in and each carton weighs 10 lbs. Based on each of the “standard” DIM factors the chargeable weight for this shipment would be:

Exhibit A - Dim Factors

DIM FactorActual WeightVolumetric WeightChargeable Weight
194500 lbs.2,062 lbs.2,062 lbs.
166500 lbs.2,410 lbs.2,410 lbs.
138500 lbs.2,899 lbs.2,899 lbs.

If we now apply a rate of $1.00/Lb to the shipment we will see that the expected charges of the shipment will vary dramatically when we base the calculation of chargeable weight on different DIM factors (See Exhibit A above).

DIM Factor Key to Calculating Shipping Cost

When you are shipping light/bulky products: The lower the DIM factor the greater the Chargeable Weight, hence a $1.00/Lb rate with a lower DIM factor will be effectively more expensive than a $1.00/Lb. rate with a higher DIM factor. To be competitive, a rate with a lower DIM factor must be less than a rate with a higher DIM factor. The chart below illustrates this point using our example shipment - the lower the DIM factor the higher the effective shipping cost.

DIM FactorApplied RateChargeable WeightExpected CostsEffective Rate
194$1.002,062 lbs.$2,062$1.00 / lb
($2,062 / 2,062 lbs. = $1.00)
166$1.002,410 lbs.$2,062$1.00 / lb
($2,062 / 2,410 lbs. = $1.17)
138$1.002,899 lbs.$2,062$1.00 / lb
($2,062 / 2,899 lbs. = $1.41)

To calculate the shipping cost for air freight, the DIM factor is critical.  When comparing one quote versus another, you must know the rates, DIM factors, and the weight & cube attributes of the products you want to ship.