Dimensional, or volumetric, weight is the single most common cause of complaints and confusion surrounding transporting goods overseas. Whether sending a single parcel or a sizeable freight consignment, businesses need to understand the calculations involved, or risk wasting considerable sums of money.

Unexpected extra charges due to volumetric weight corrections are never welcome. Producers and suppliers need to understand that most shipments, particularly airfreight, are now not billed by weight alone, but also the volume of an item or consignment.

What is dimensional weight?

The idea behind billing by dimensional weight is simple. The space inside the cargo belly-hold of an aircraft, for example, is quite restricted; so too is the weight of all the items the aircraft can carry. Otherwise, it couldn’t take off. A carrier must take into account both the weight and overall size of a shipment. This is called its dimensional or volumetric weight. The term “dimensional weight” is mostly used in the USA and “volumetric weight” in the UK and Europe.

Although originally used as a calculation to charge for the space inside the hold of an aircraft, most carriers have extended the use of volumetric measurements to ships and surface transport today.

That means, for almost all international shipments and most domestic shipments, a carrier will charge on weight or volume (calculated as volumetric weight), whichever is the greater. If a parcel is relatively light but takes up a lot of room, perhaps due to extensive packaging, that needs to be considered when the carrier works out how much to charge for the shipment.

How to calculate volumetric weight

Volumetric weight is calculated by multiplying the length, width and height of a parcel (usually in cm for UK and EU shipments and inches for US shipments) and then dividing that figure. The big problem is that different carriers use different divisors. And some apply a different volumetric formula for their express service compared to their economy service.

Depending on the carrier, the final figure is divided by 4,000, 5,000 or 6,000 to determine the billable volumetric weight:

• Courier: If you’re sending with an express courier such as UPS or FedEx, the devisor will likely be 5,000. So the calculation is length (cm) x width (cm) x height (cm) ÷ 5,000.
  • If you are shipping from the US using a US-based carrier the calculation is length (in) x width (in) x height (in) ÷ 139
• Freight: If you’re sending air freight or road/economy freight, the divisor will likely be 6,000. So the calculation is length (cm) x width (cm) x height (cm) ÷ 6,000
• Economy: Some other companies, such as TNT (which is currently merging with FedEx), use a slightly different formula for their economy service, dividing by 4,000. So the calculation is length (cm) x width (cm) x height (cm) ÷ 4,000

Volumetric weight calculator

You are probably thinking by now that you are going to need to hire an Einstein or Newton simply to calculate your shipping costs. Happily, ParcelHero has an easy-to-use tool that calculates exactly what the volumetric weight of a parcel will be, for each carrier service.

Furthermore, if you enter the specific carrier and service you are thinking of booking, it will calculate the exact volumetric weight you will be billed for. No more unexpected extra charges.

How to reduce dimensional weight

The key to avoiding the hefty costs sometimes associated with dimensional weight calculations is to ensure the items are not only carefully padded and sealed (to safely withstand the rigours of being handled at airports and Customs) but also packaged as tightly as possible.

If you are a manufacturer or have any control in the packaging of the items you ship, it’s well worth considering these issues in the design of your boxes, etc. It’s amazing how many products are still distributed in packaging that looks great on the shelves, but wastes space unnecessarily, leading to considerably higher transport costs than are really necessary.

Mastering how your chosen carriers calculate their dimensional weight charges is easier than it first appears (especially if you use ParcelHero’s calculator) and an essential tool in keeping your supply chain costs down.

David Jinks is the head of consumer research at international delivery expert ParcelHero. He is a member of the Chartered Institute of Logistics & Transport and was formerly editor of Logistics & Transport Focus

Further reading

Here are the EU Four VAT Quick Fixes and how to deal with them – The EU Four VAT ‘Quick Fixes’ came into effect on January 1 2020, promising seismic change for the way British companies export to Europe. Are you ready?

How to manage the post-Brexit customs process for trading in Europe – UK businesses will continue to operate post Brexit but the customs process does need some consideration. Andrew Hubbard and Brad Ashton of accountants RSM analyse what exporters within and without the EU need to be doing now