Dimensional weight (or DIM weight) is the weight of a package based on its size rather than "actual weight". UPS, FedEx, and USPS calculate a dim weight for their services and charge the greater of the actual scale weight or dim weight to price packages, when applicable. Dimensional weight impacts the pricing of a package because the carrier will charge a higher price between dimensional weight and actual weight. To summarize, if your package is lightweight but large (like a canvas painting or a pillow), it will cost more to ship.
Calculating Dimensional Weight for USPS
When using USPS, dimensional weight pricing only applies to packages larger than 1 Cubic Foot and when using Priority, Priority Express, and Ground Advantage. If the result is more than 1 Cubic Foot (1728 cubic inches), divide the result by 139 to determine the dimensional weight.
To calculate dim weight follow the steps below.
Measure the length, width, and height in inches of a package, using the longest point on each side. Round up each measurement to the nearest whole number. Any fraction of an inch will be rounded up to the next whole inch. (For example, 9.01 to 9.99 will be considered 10.)
Next, multiply the length x width x height. This equals the total amount of cubic inches for the package.
Finally, divide the cubic inches by 139 to get the dimensional weight.
Example USPS
If your package is 16 inches by 12 inches by 10 inches. 16"x12"x10"=1920 cubic inches.
Since 1,920 cubic inches is over the 1,728 one cubic foot threshold—your package will qualify for DIM pricing.
Divide 1920 by 139 to get a dimensional weight of 13.81 (14) pounds.
If the actual weight of the package is less than 14 pounds (e.g., 12 pounds), USPS will charge for the dimensional weight of 14 pounds since it is the greater number.
If the actual weight of the package is more than 14 pounds (e.g., 17 pounds), the pricing will be based on the actual weight, not the dimensional weight, since they charge for the greater number.
If you have entered in your dimensions and weight correctly in XPS Ship, it will automatically calculate correctly if your package qualifies for dimensional weight or actual weight, and displays in the quote box.
Calculating Dimensional Weight for FedEx and UPS shipments
To calculate dim weight for shipments you would use the same steps as above, and use 139 as the divisor.
Measure the length, width, and height in inches of a package, using the longest point on each side. Round up each measurement to the nearest whole number. Any fraction of an inch will be rounded up to the next whole inch. (For example, 9.01 to 9.99 will be considered 10.)
Next, multiply the length x width x height. This equals the total amount of cubic inches for the package.
Finally, divide the cubic inches by 139 to get the dimensional weight.
Example FedEx and UPS
If your package is 30 inches by 12 inches by 12 inches. 30"x12"x12"=4,320 cubic inches.
Divide 4,320 by 139 rounded up to get a dimensional weight of 32 pounds.
If the actual weight of the package is less than 32 pounds (e.g., 29 pounds), the carrier will charge for the dimensional weight of 32 pounds since it is the greater number.*
If the actual weight of the package is more than 32 pounds (e.g., 33 pounds), dimensional weight pricing will be based on the actual weight, not the dimensional weight, since they charge for the greater number.
If you have entered in your dimensions and weight correctly in XPS Ship, it will automatically calculate correctly if your package qualifies for dimensional weight or actual weight, and displays in the quote box.
*Exceptions: If you are using your own FedEx or UPS account, Contract-specific or negotiated volume rates can alter your assigned divisor if agreed upon with the carrier.