Definition
Dim Weight (short for Dimensional Weight or Volumetric Weight) is a shipping pricing method that charges for a package based on its size rather than its actual weight. Carriers compare the package’s dimensional weight with its physical weight and bill whichever is greater.
Expanded Explanation
Large packages take up valuable space in delivery vehicles and aircraft, even if they are lightweight. To reflect this, shipping companies calculate dim weight using the package’s dimensions:
Dimensional Weight = (Length × Width × Height) ÷ Dimensional Factor
The dimensional factor varies by carrier and shipping service.
For dropshipping businesses, dim weight is especially important when selling bulky but lightweight products, such as pillows, storage boxes, lampshades, or plush toys. These products may cost significantly more to ship than their actual weight suggests.
Using compact packaging can help reduce dimensional weight and lower shipping costs.
Example
A dropshipping store sells a decorative pillow that weighs 1 kg (2.2 lb). It is packed in a box measuring 50 × 40 × 30 cm.
Assume the carrier uses a dimensional factor of 5,000.
Dimensional Weight = (50 × 40 × 30) ÷ 5,000 = 12 kg
- Actual weight: 1 kg
- Dimensional weight: 12 kg
Because the dimensional weight is higher than the actual weight, the carrier charges shipping based on 12 kg, not 1 kg.
This is why bulky but lightweight products often cost much more to ship than sellers expect.
Note: The dimensional factor varies by carrier and shipping service. Common divisors include 5,000 (cm-based international shipments) and 139 (inch-based shipments used by some U.S. carriers).
Why It Matters
Understanding dim weight helps eCommerce sellers:
- Estimate shipping costs more accurately
- Price products with better profit margins
- Reduce fulfillment expenses through smarter packaging
- Avoid unexpected carrier charges for oversized parcels
For many dropshipping businesses, optimizing package size can be just as important as reducing product weight.