Volumetric weight: why your 4 kg box is billed as 14 kg
Air freight from China to Bangladesh bills the higher of actual and volumetric weight, calculated as length × width × height in cm divided by 5000. Here is how to calculate it before you order, and what to do about bulky goods.
Air freight bills the higher of your actual weight and your volumetric weight, where volumetric weight is length × width × height in centimetres divided by 5000. A 4 kg box measuring 60 × 40 × 30 cm bills as 14.4 kg — so a light, bulky product can cost three times what the scale suggests. Sea freight is priced by volume and is far more forgiving of bulk.
The formula
volumetric weight (kg) = (length × width × height in cm) ÷ 5000
You pay on whichever is greater: that number, or what the scale says.
Worked example. A carton of pillow filling weighs 4 kg and measures 60 × 40 × 30 cm.
- Actual weight: 4 kg
- Volumetric: (60 × 40 × 30) ÷ 5000 = 72,000 ÷ 5000 = 14.4 kg
- Billed: 14.4 kg × ৳750 = ৳10,800, not the ৳3,000 you budgeted
That gap is where first-time importers lose their margin.
Which products get hurt
Anything with a low density — a lot of box for not much mass:
- Foam, filling, cushions, pillows
- Plush toys
- Lampshades, artificial flowers, decorative baskets
- Empty containers, bottles, storage boxes
- Anything shipped in oversized display packaging
Dense products have the opposite problem, in a good way: hardware, tools, small electronics, industrial components and cosmetics almost always bill at actual weight, so air freight is efficient for them.
Check before you order, not after
The 1688 listing shows a gross weight (毛重) per piece and often the carton dimensions. Two minutes of arithmetic before you order:
- Multiply the per-piece weight by your quantity → actual kg.
- Take the carton dimensions, multiply the three numbers, divide by 5000 → volumetric kg per carton, then multiply by the number of cartons.
- Whichever is larger is what you will pay on.
If volumetric is more than about 1.5× actual, stop and reconsider the lane.
What to do about a bulky product
- Move it to sea. Sea freight is ৳280 per kg with a 2 kg minimum and takes 30–35 days. For bulky, non-urgent goods the saving is dramatic.
- Ask for it to be re-packed. Factory packaging is often wasteful — retail boxes inside a carton with air around them. Flattening and re-packing at the consolidation warehouse can cut volumetric weight meaningfully.
- Reconsider the product. Some products simply do not survive the freight maths at Bangladesh's typical retail prices. Better to learn that from a calculation than from a shipment.
Why the divisor is 5000
It is an airline convention that converts space into a weight-equivalent, because an aircraft runs out of room before it runs out of lifting capacity. A divisor of 5000 means one cubic metre is treated as 200 kg. It is not a fee invented by your forwarder — it is how air cargo is priced worldwide.
Frequently asked questions
- How do I calculate volumetric weight?
- Multiply length by width by height in centimetres and divide by 5000. You are billed on that figure or the actual scale weight, whichever is higher.
- Why is my shipping cost higher than the product weight suggests?
- Because the box is bulky relative to its mass. A 4 kg carton measuring 60 by 40 by 30 cm has a volumetric weight of 14.4 kg, and that is what air freight charges on.
- Which products suffer most from volumetric weight?
- Low-density goods: foam and filling, plush toys, lampshades, artificial flowers, empty containers and anything in oversized display packaging.
- What can I do about a bulky product?
- Ship it by sea at ৳280 per kg, ask for the factory packaging to be re-packed flat at the consolidation warehouse, or accept that the product does not work at Bangladeshi retail prices.
- Why is the divisor 5000?
- It is a worldwide air-cargo convention that turns space into a weight equivalent, because an aircraft runs out of room before it runs out of lifting capacity. One cubic metre is treated as 200 kg.