What is Dimensional weight and how does it work?

Dimensional (DIM) weight, also known as volumetric weight, is used to calculate the rate of big, lightweight packages. DIM may be applied to Priority Mail parcels, Ground Advantage (GA), and Global Express Guaranteed (GXG) parcels.

For Global Express Guaranteed parcels, the DIM price is applied when the item is not mailed in a USPS-produced GXG envelope and the dimensional weight price is greater than the postage calculated based on the item’s per-pound weight.

To calculate DIM weight multiply the length, width, and height of a package, using the longest point on each side. One should round up each measurement to the nearest whole number.

For example:  The measurement between 7.00 to 7.49 will be considered a 7; and the measurement between 7.50 to 7.99 will be considered an 8.

If the result is greater than 1728 inches, 1 cubic foot, divide it with a dimensional divisor to determine the DIM weight. The current Postal Service dimensional divisor is 166, and it applies to all zones. 

DIM weight = Length x Width x Height ÷ 166

The customer will be charged the greater of the DIM weight or the actual scale weight.