How to calculate Dimensional Weight

The dimensional weight is the actual cost of the package based on the rated weight. The Rated weight is calculated based on the l x w x h divided by a factor called the dimensional factor (or dim divisor).

Dimensional weight represents the actual cost of shipping a package based on its rated weight. The rated weight is calculated by multiplying the package's length, width, and height (l x w x h) and then dividing the result by a factor known as the dimensional factor (or dim divisor).

The term "weight" can be somewhat misleading when discussing dimensional weight. Instead of reflecting the actual weight of a package, dimensional weight (or dim weight) indicates its density—essentially, how much space it will occupy in a carrier's freight vehicle or airplane. You can think of it as a theoretical weight, as it represents the weight a package should be considered to have based on its size. 

To calculate a package's dimensional weight:

1. Measure the Package: Ensure that you measure the package's dimensions at their extremes—length, width, and height. Keep in mind that the dimensions provided by box manufacturers may not accurately reflect the package's true size.

2. Calculate the Cubic Size: Multiply the length, width, and height to obtain the cubic volume of the package.

3. Divide by the Dimensional Factor (Dim Divisor): The value of the dim divisor varies by carrier. For domestic ground shipments, common divisors are 139 and 166, while for international air shipments, use a divisor of 139. Be aware that dim divisors can change, so it's important to consult your carrier for the most current information.

4. Round Up: Carriers will round up to the nearest whole number, so make sure to do the same in your calculations.

For example:

Say you're using UPS ground service to send a package. Your box measures 24″ x 18″ x 18″ and the parcel weighs 50 lbs. 

1. You must multiply 24 by 18 by 18 to determine the cubic size. That results in 7,776 cubic inches.
2. The applicable dim divisor is 139 because you're shipping ground and the shipment is over 1,728 cubic inches (specific to UPS).
3. Dim weight = 7,776 / 139. The result is 55.9 lbs.
4. 55.9 lbs. and can be rounded up to 56 lbs.

The dim weight (56 lbs.) will be used in calculating the shipping costs because it is greater than the actual weight (50 lbs.).

Let's assume that something weighing 65 lbs is being shipped in the same size box. The actual weight of 65 lbs. is found to be more than the dim weight, so the actual weight of 65 lbs. will be the billable weight. 

Example Calculation of Dimensional Weight

Let’s consider a scenario where you're using UPS Ground service to send a package. The dimensions of your box are 24″ x 18″ x 18″, and the package weighs 50 lbs.

1. Calculate the Cubic Size: Multiply the dimensions:

   

2. Determine the Dimensional Divisor: For UPS Ground service, the applicable dim divisor is 139, as the shipment exceeds 1,728 cubic inches.

3. Calculate Dimensional Weight:

   
   

   Round up to the nearest whole number, which gives you a dim weight of 56 lbs.

4. Determine Billable Weight: Since the dim weight (56 lbs.) is greater than the actual weight (50 lbs.), the shipping costs will be calculated based on the dim weight of 56 lbs.

Now, let’s consider another scenario: if you are shipping an item that weighs 65 lbs in the same size box. In this case, the actual weight of 65 lbs exceeds the calculated dim weight of 56 lbs. Therefore, the billable weight will be the actual weight of 65 lbs.