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How to Calculate DIM Weight – Definition and Effects on Pricing

October 14, 2020 Published by

a weight scale

Dimensional weight, or DIM weight, has always been around for the air shipping industry. In 2007, ground carriers began charging for DIM weight to protect themselves from the cost of transporting lightweight packages that took up lots of cargo space. The term dimensional “weight” is somewhat of a misnomer; the package’s volume or “dimension” is what’s actually being measured. But, this is converted into a theoretical weight – what the package could be expected to weigh given how much space it occupies.

For packages larger than 3 cubic feet, carriers will calculate the DIM weight and charge for whichever is greater – the actual weight or the DIM weight. Among the shipping tips your business should know, understanding how to calculate DIM weight is crucial. To find out which rate you’ll pay for your packages, here’s how to calculate DIM weight.

4 Easy Steps To Calculate DIM Weight

  1. Using the longest point on each side, measure the length, width and height of your package. Your measurements need to consider any bulges or misshapen sides, as any deformities can call for special handling fees if they are not included in the initial dimensional weight calculations.measuring length width height of box
  2. When you calculate dimensional weight, most shipping carriers request you round to the nearest whole number.rounding up to 2
  3. Multiply your package dimensions to calculate its cubic size. For example, if your package is 20 inches by 10 inches by 10 inches, your package size is the result of these three measurements multiplied: 2,000 cubic inches.

cubic size formula


  1. The final step is to divide the cubic size of your package by a dimensional factor, also known as a DIM divisor. DIM divisor numbers are set by major freight carriers like the UPS and FedEx. This number represents cubic inches per pound.

dim divisor formula

  • In this case, your package is 2,000 cubic meters, weighs 30 pounds, and you are shipping by ground.
  • Your DIM divisor in this example will be 139 based on FedEx’s DIM weight divisor. As a result, the dimensional weight of your package is 14 – this is less than your package’s actual weight, which means you would be charged for the actual weight.

Get The DIM Weight Right

Depending on the DIM weight of the packages you ship, your shipping expenses may increase. As such, learning how to keep dimensional weight costs down is an important next step to take.