Volumetric weight explained
Couriers charge for the space a parcel takes up as well as its weight. That is why a big, light box can cost more than a small, heavy one. The space-based figure is called volumetric weight (or dimensional weight), and once you know how it works you can often lower what you pay.
How to calculate volumetric weight
Measure the box at its widest points in centimetres, then:
Length × width × height ÷ 5000 = volumetric weight in kg
The courier then compares this with the actual weight on the scale and charges whichever is greater. That figure is called the chargeable weight.
A worked example
| Box | Calculation | Volumetric weight | Actual weight | Charged as |
|---|---|---|---|---|
| 50 × 40 × 30 cm | 60 000 ÷ 5000 | 12 kg | 4 kg | 12 kg |
| 30 × 20 × 15 cm | 9 000 ÷ 5000 | 1.8 kg | 3 kg | 3 kg |
The first box is mostly air, so it is charged on its size. The second is small and dense, so it is charged on its actual weight.
Try the calculator
Why couriers use volumetric weight
Vehicles and aircraft run out of space before they run out of weight capacity. A van full of large, light boxes earns the same as a van carrying a fraction of the load if only weight counted. Volumetric weight makes pricing fair for everyone sharing the space.
Is the divisor always 5000?
5000 is the most common divisor for courier services in South Africa. Some carriers use a different figure for certain services, for example 4000 on some economy road products, and air cargo is often calculated differently. That is why the chargeable weight is always confirmed on your quote.
How to keep your costs down
- Use the smallest box that fits safely. Every centimetre counts because the three measurements are multiplied together.
- Avoid oversized boxes stuffed with padding. Use enough padding to stop movement, not to fill empty space.
- Combine items sensibly. Two small parcels can cost more than one well-packed box, or less, depending on their sizes. We can advise.
- Measure before you book. Accurate dimensions mean an accurate quote and no surprises on the invoice.
For more packing tips, read how to pack a parcel so it arrives safely, or compare our courier options to see which service suits your parcel.
Need to send something? Tell us what it is and where it's going, and we'll send a clear price.
Get a Quote