Dimensional weight calculator
Find the dimensional weight and billable weight of a package. Enter the outside measurements of the box and pick your carrier's divisor.
What dimensional weight is
Dimensional weight, often shortened to DIM weight, is a pricing method that charges for the space a package takes up in a truck or plane rather than just how heavy it is. A large box of pillows weighs little but fills as much space as a box of books, so carriers price it by size.
The formula
Multiply the outside length, width and height, then divide by the carrier's divisor.
Centimeters and kilograms: L × W × H ÷ 5000 (or 6000)
For example, a 12 × 10 × 8 inch box has a cubic size of 960 cubic inches. Divided by 139, that's 6.9, which rounds up to 7 pounds. If the package actually weighs 4 pounds, you'll pay for 7.
Rounding rules
Carriers typically round each measurement to a whole inch and round the result up to the next whole pound. This calculator rounds each side up, which is the cautious choice and matches how a measuring machine can treat fractions. For metric divisors, the result is rounded up to the next half kilogram.
How to reduce what you pay
- Size the box around the product plus the cushioning it actually needs. The box size calculator does this for you.
- Compare against standard box sizes before ordering. A box one step smaller can save a pound or more on every shipment.
- Ship soft, unbreakable items in poly mailers instead of cartons.
- For high volumes, a custom box made to your inside dimensions usually pays for itself in shipping savings.
Divisors and rules are set by each carrier and can change at any time. Always confirm with your carrier or contract before quoting shipping costs.
Frequently asked questions
What is the dimensional weight divisor for UPS and FedEx?
UPS and FedEx commonly use 139 for daily and account rates when measuring in inches and pounds. Retail counter rates can use 166. Divisors change and some contracts use custom values, so confirm yours with the carrier.
Does USPS charge dimensional weight?
USPS generally applies dimensional pricing only to packages larger than one cubic foot (1,728 cubic inches), using a divisor of 166. Smaller packages are charged on actual weight.
Which weight will I be charged for?
Carriers compare dimensional weight with actual weight and bill the higher of the two. That figure is called the billable weight.
How do I lower dimensional weight?
Use the smallest box that protects the product. Trim the cushioning to what the product actually needs, avoid rounding up to a much larger stock box, ship soft goods in poly mailers, and consider a custom box built to your inside dimensions.