Dimensional vs Actual weight:
What’s the difference?


Dimensional weight not only plays a key role in how shipping costs are calculated, it helps carriers balance the space your package takes up with the cost to ship it. Understanding dimensional vs actual weight and how to calculate its formula can help your business avoid extra fees and save money.

What Is Dimensional Weight?

Dimensional weight,or volumetric weight, is how carriers determine shipping costs based on the amount of space a package occupies, rather than just its actual weight.The dimensional factor (DIM factor) is what carriers use to turn a package’s volume into dimensional weight. It shows how much space equals one pound of billable weight.

Dimensional  Factors to consider:

  • 139: Standard for U.S. domestic shipping (FedEx, UPS, etc.).
  • 166: Used for international shipping, where space is tighter.

How to Calculate Dimensional Weight

To calculate dimensional weight, use this formula:


(LengthxWidthxHeight)÷DimensionalFactor(Length x Width x Height) ÷ Dimensional Factor(LengthxWidthxHeight)÷DimensionalFactor

Example Calculation:
A box measuring 16” x 16” x 16”( the size of a standard Medium cardboard box)  with a dimensional factor of 139:

(16x16x16)÷139=30lbs(dimensional weight)(16 x 16 x 16) ÷ 139 = 30 lbs (dimensional weight)(16x16x16)÷139=30lbs(dimensional weight)

If the package’s actual weight is 20 lbs, you’ll be charged for 30 lbs, as the dimensional weight is higher.

What Is Actual Weight?

Actual weight is the literal weight of your package when it’s measured on a scale. Unlike dimensional weight, it doesn’t consider the package size, only the actual  physical mass of the item.

Dimensional Weight vs Actual Weight: What’s the Difference?

  • Dimensional Weight: Based on package size and calculated using the dimensional weight formula.
  • Actual Weight: The physical weight of the package measured on a scale.
  • Why It Matters: Carriers charge for whichever weight is greater. Large but lightweight packages can  often incur higher charges due to their  dimensional weight.

How to Lower Shipping Costs By Calculating Dimensional Weight

  • Optimize Your Packaging
    • Use boxes that fit your products snugly to reduce empty space.
    • Avoid oversized boxes or excessive packing materials that increase dimensional weight.
  • Freight Calculators
    • Before shipping, calculate both dimensional and actual weight to predict costs accurately.
    • Many carriers provide online freight calculators for quick estimates.
  • Partner with ProPack
    • ProPack offers businesses  customized solutions to optimize their  packaging and 3PL logistics strategies, helping businesses reduce dimensional weight costs while maintaining product safety.

Understanding and mastering the difference between dimensional weight and actual weight is key to controlling your business or consumer’s  shipping costs. By calculating both and optimizing your packaging, you can avoid unnecessary charges or unexpected (and costly) shipping surcharges or other expenses. Let the experts at ProPack Logistics help you implement smarter shipping strategies to save money and streamline your distribution operations.