Volumetric Weight Explained: Why Big, Light Parcels Cost More to Ship
Volumetric Weight Explained: Why Big, Light Parcels Cost More to Ship
TL;DR: Carriers charge for space as well as weight. If your parcel is large but light, you pay for its volumetric weight, worked out from its length, width and height, rather than what it weighs on the scales. Whichever is higher becomes the chargeable weight. Smaller boxes, less packaging and consolidation can bring the cost down noticeably.
What Is Volumetric Weight?
Planes and delivery vans fill up by space as well as by weight. A large box of pillows takes up as much room as a box of books, but weighs far less. To make sure bulky parcels pay their fair share, carriers work out a weight based on size, called volumetric weight or dimensional weight, and compare it with the actual weight.
At Send2Hub we see this every day. Duvets, toys and shoe boxes are often charged by volumetric weight, and clothing regularly arrives in polybags far bigger than the items inside.
How to Calculate Volumetric Weight
Measure the length, width and height of the parcel in centimetres, multiply them together and divide by 5,000. The result is the volumetric weight in kilograms.
Example: a box of 50 × 40 × 30 cm gives 60,000 ÷ 5,000 = 12 kg. If the box actually weighs 4 kg, it's charged as 12 kg.
Volumetric Weight Formula
Volumetric weight (kg) = Length × Width × Height (cm) ÷ 5,000
Some carriers use a divisor of 4,000 for express air services, which makes the volumetric weight higher. Our shipping calculator uses 5,000 for every carrier and service, and works it out automatically when you enter the dimensions.
Actual Weight vs Chargeable Weight
The chargeable weight is whichever is higher: the actual weight or the volumetric weight. Here's how that works for three typical parcels:
| Parcel | Size (cm) | Actual weight | Volumetric weight | Chargeable weight |
| Box of books | 30 × 20 × 20 | 10 kg | 2.4 kg | 10 kg |
| Duvet | 60 × 40 × 40 | 3 kg | 19.2 kg | 19.2 kg |
| Trainers in a shoebox | 35 × 25 × 15 | 1.5 kg | 2.6 kg | 2.6 kg |
Heavy, compact items are charged by actual weight. Light, bulky items are charged by volumetric weight.
Items That Often Catch People Out
Duvets, pillows and cushions, padded coats, children's toys and boxed LEGO sets, wheel and tyre boxes, lampshades, gift hampers and shoes in their original boxes. Clothing is a common surprise too, because retailers often send it in polybags or boxes much larger than needed.
How to Reduce Volumetric Weight
Consolidate your orders. One well-packed box is usually cheaper than several half-empty ones. Parcel consolidation is free and typically cuts shipping by 40 to 60%.
Remove bulky packaging. When we consolidate, we can remove the original shipping packaging for £20 + VAT per consolidated shipment up to 30 kg, which can make a big difference for oversized boxes.
Vacuum packing for small soft items. We can vacuum pack small soft items, such as clothing, to save space. Just ask before you request shipping.
Choose smaller or flat-packed items. Where a retailer offers flat-packed versions, they usually cost less to ship.
Compare options. With very large boxes, sending them separately can sometimes be cheaper than combining them, so check both in the calculator.
Watch the weight bands. Prices jump above 30 kg, so parcels of around 15 to 25 kg are often the best value.
For more ways to save, see our guide on how to reduce international shipping costs, and if you're sending something delicate, read our guide to shipping large or fragile items.
Check the Real Cost Before You Buy
Look for the boxed dimensions in the product listing, or ask the seller, then enter them in our shipping calculator. You'll see the real cost of shipping before you order, with no surprises later. Compare Royal Mail, Parcelforce, UPS, DHL, FedEx and DPD in one place.
Frequently Asked Questions
What is volumetric weight?
It's a weight carriers calculate from a parcel's size, so that large, light parcels are charged fairly for the space they take up.
How do I calculate volumetric weight?
Multiply length, width and height in centimetres and divide by 5,000. The result is the volumetric weight in kilograms.
Which weight do I pay for?
Whichever is higher: the actual weight or the volumetric weight. This is called the chargeable weight.
Can volumetric weight be higher than actual weight?
Yes. Large, lightweight parcels are often charged by volumetric weight rather than their actual weight.
Do all couriers use the 5,000 divisor?
No. Some carriers use 4,000 for express air services. The Send2Hub shipping calculator uses 5,000 for every carrier.
Why does my parcel cost more than I expected?
It's probably large for its weight, so it's being charged by volumetric weight. Consolidating and removing bulky packaging can help.
How can I reduce volumetric weight?
Consolidate your orders, remove oversized packaging, choose flat-packed items and compare sending boxes together or separately.