Volumetric weight explained with examples
Why a big, light box can cost more than a small, heavy one, and how to calculate volumetric weight before you ship.
You weigh a parcel at 2 kg, but the invoice says 5 kg. That is not a mistake. It is volumetric weight, and once you understand it you can lower your shipping bill.
What is volumetric weight?
Couriers have limited space in vans and aircraft. A large, light box takes up as much room as a heavy one, so it is charged by size as well as weight.
Volumetric weight (also called dimensional or volume weight) turns the size of a box into a weight:
Volumetric weight (kg) = Length × Breadth × Height (cm) ÷ 5000
You are charged on whichever is higher: the actual weight or the volumetric weight. This is called the chargeable weight.
Example 1: a pillow
- Box: 50 × 40 × 30 cm
- Actual weight: 1.2 kg
- Volumetric weight: 50 × 40 × 30 ÷ 5000 = 12 kg
Chargeable weight: 12 kg. The size, not the weight, sets the price.
Example 2: a box of books
- Box: 30 × 20 × 15 cm
- Actual weight: 6 kg
- Volumetric weight: 30 × 20 × 15 ÷ 5000 = 1.8 kg
Chargeable weight: 6 kg. Here the actual weight is higher, so it is used.
Example 3: a shoe box
- Box: 40 × 30 × 20 cm
- Actual weight: 3 kg
- Volumetric weight: 40 × 30 × 20 ÷ 5000 = 4.8 kg
Chargeable weight: 4.8 kg, which is billed in 500 g slabs as 5 kg.
How to lower your chargeable weight
- Use the smallest box that protects the item. Every centimetre counts because the three sides multiply.
- Use poly mailers for soft goods. Clothes and textiles rarely need a box.
- Measure after packing. Measure the outer box, including any bulge, not the product.
- Round honestly. If your declared size is smaller than the real one, the courier will reweigh and charge the difference.
Avoiding weight disputes
Most weight disputes happen because the seller declared the product weight, not the packed weight. Weigh and measure the final parcel.
ZipNexa Weight Guard records the weight and photos at pickup, so if there is ever a difference, it comes with proof. You can raise a dispute from your dashboard within the window shown in your dashboard.
Try it
Enter your box size and weight in the Rate Calculator. It shows the volumetric weight and the price for express, surface and air in seconds.