Dimensional weight, also called volumetric weight, is a pricing technique for commercial freight transport (including courier and postal services), which uses an estimated weight that is calculated from the length, width, and height of a package. To determine the dimensional weight, multiply the package’s length x width x height (L x W x H). The result of this calculation is then divided by a number called the DIM factor, which represents cubic inches per pound and is related to the package’s density. Common DIM factors include 139 and 166, but carriers use other ones as well.


For example, assume a 1-pound package has a length of 12 inches, a width of 10 inches, and a height of 7 inches. The carrier has provided a DIM factor of 139. To calculate DIM weight, use the following formula: (12 x 10 x 7) / 139, as follows:


  1. Multiply 12” x 10” x 7”. This gives us the package’s volume, 840 cubic inches.
  2. Divide 840 by 139. The result is roughly 6.04.


Thus, the DIM weight of the package is 6.04 pounds.


Actual Weight Or DIM Weight?

When determining shipping price, the higher of the DIM Weight or actual weight is used. Thus, in our example, a weight of 6.04 pounds would be used instead of 1 pound. Also, take note that many shipping carriers round weights up to the nearest pound, so it is likely you would be charged a rate based on a 7-pound package for this shipment.


Other Considerations

The above example assumes the use of the United States Customary System of measurements. If you’re using the metric system, your units will be centimeters and kilograms and the DIM factor will change accordingly (a DIM factor of 5000 cubic centimeters per kilogram is commonly used).


Many carriers ask you to round your measurements to the nearest whole number. So, if your package has a length of 5.75”, round up to 6”. If the package length is 5.45”, round down to 5”.


Important Takeaways

Here are the most important points to remember about DIM Weight:

  • Dimensional (DIM) weight is also called Volumetric Weight
  • It’s a pricing technique used to determine the cost of shipping based on a package’s size and density
  • It’s calculated as follows: (L x W x H) / DIM Factor = DIM weight
  • The DIM factor is determined by the carrier. It is often 139 or 166, or 5000 if the metric system is being used
  • The greater of actual weight or dimensional weight is used to determine the shipping price


Dimensional weight can have a huge impact on the cost of shipping. With that in mind, always pack your items efficiently, using the smallest shipping carton you can while still keeping the products safe and secure.