What is dimensional weight?

What is dimensional weight?
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At FedEx, the price of your shipment is based either on your package’s dimensional (dim) weight or the actual weight of the package — whichever is greater.


What is dim weight?

Dim weight reflects the amount of space a package occupies in relation to its actual weight. It applies to both FedEx Express and FedEx Ground packages when your package is relatively light compared with its volume.


A photo of a FedEx box and its dimensions, showing how to calculate dimensional weight


Dim weight is calculated by:

  1. Multiplying length by width by height in inches. Round each measurement to the nearest whole inch. The resulting total is the cubic size of your package.
  2. Dividing by 139 for U.S., Puerto Rico, and international shipments.1


Need a little help with the math? Check out this dimensional weight calculator designed to help you easily calculate the dim weight of your packages. Calculating dim weight can seem complicated, but using it correctly will save your business money.


Additional information

For additional information on the best way to optimize your packaging, check out the FedEx Packaging Services page of the FedEx Service Guide.


Hands-on help

If you’d like FedEx to help you select the correctly sized packaging for your items, learn more about FedEx® Pack Plus.


1Effective Jan. 2, 2017, the dim weight calculation for FedEx Express and FedEx Ground packages changed. Previously, dim weight for all shipments within the U.S. and FedEx Express shipments between the U.S. and Puerto Rico was calculated by dividing the total by 166. See the FedEx Service Guide for more information.