Volumetric weight is a weight derived from the space cargo occupies in transport rather than from what it registers on the scale. It exists to price large, light shipments fairly, since they take up room without weighing much.
Volumetric weight is how carriers charge for the space a shipment takes up on the aircraft. Multiply length by width by height in centimetres and divide by 5,000, piece by piece. The amount billed follows the greater of actual and volumetric weight. Source: DHL Express Service and Rate Guide 2026 Brazil.
Anyone who has opened an international freight invoice well above expectations has probably met this rule. The scale read 7 kg, the bill came to 19.5 kg, and the difference was not in the product. It was in the box.
How do you calculate volumetric weight?
Three operations. A tape measure and a calculator will do:
- Measure length, width and height of each piece in centimetres, with the packaging already closed.
- Multiply the three figures to get the volume of that piece in cubic centimetres.
- Divide the result by 5,000. The number you get is the volumetric weight of that piece, in kilos.
The calculation runs piece by piece. On a multi-piece shipment, add up the volumetric weights and compare the total with the sum of the actual weights.
An everyday example. A box of 60 cm by 40 cm by 40 cm comes to 96,000 cubic centimetres. Divided by 5,000, that is 19.2 kg of volumetric weight. If the equipment inside weighs 7 kg, the higher figure is the one that counts: billing starts from 19.2 kg, not from 7 kg.
Why is the divisor 5,000?
Because it translates the density air transport treats as normal. DHL Express states in its own guide that this is a standard IATA method, used whenever the volumetric weight of a large, light package exceeds the weight on the scale.
Run the maths backwards and the divisor makes sense. One cubic metre holds 1,000,000 cubic centimetres. Divided by 5,000, that gives 200 kg per cubic metre. There is the dividing line: anything denser than that is charged by actual weight, anything lighter is charged by volume.
Pillows, lamps, injection moulded parts and boxes packed with bulky void fill almost always sit below 200 kg per cubic metre. Bearings, machined parts, books and metal components almost always sit above it.
Does the carrier charge actual or volumetric weight?
The greater of the two, and the figure then goes through rounding. The rate guide is explicit: every shipment goes through a reweighing process, and the amount finally charged follows the actual or volumetric weight, whichever is higher.
Rounding comes in two bands. Billing weight is rounded up to the next 0.5 kg for shipments up to 30 kg, and to the next 1 kg above that. Each individual piece is also rounded up to the next 0.5 kg. Source: DHL Express Service and Rate Guide 2026 Brazil.
Back to the box in the example: 19.2 kg of volumetric weight becomes 19.5 kg of billing weight. Those are 300 grams. Trivial on one shipment, they add up to 30 kg at the end of a month in which the operation dispatched a hundred pieces, paid only because nobody checked the height of the box before sealing it.
Can volumetric weight trigger a surcharge?
It can, and this is the part that catches people out. The overweight piece surcharge applies to any piece, pallets included, whose actual or volumetric weight exceeds 70 kg. A light, oversized box can reach that threshold without ever coming close to it on the scale.
There is also an oversize piece surcharge, applied when the longest side exceeds 100 cm or the second longest side exceeds 80 cm. Any single piece above 70 kg has to travel on a pallet, as the guide to palletising cargo explains.
What does an oversized box actually cost?
It costs the difference in volumetric weight. You can model that before buying any packaging, with a tape measure and three lines of a spreadsheet. The table compares three boxes for the same 7 kg product:
Box (L x W x H) | Volume | Volumetric weight | Actual weight | Billing weight |
60 x 40 x 40 cm | 96,000 cm³ | 19.2 kg | 7 kg | 19.5 kg |
50 x 35 x 30 cm | 52,500 cm³ | 10.5 kg | 7 kg | 10.5 kg |
40 x 30 x 25 cm | 30,000 cm³ | 6.0 kg | 7 kg | 7.0 kg |
From the first row to the third, billing weight drops from 19.5 kg to 7 kg. Same product, same route. What changed is the air travelling with it. In the third box actual weight finally overtakes volumetric weight, and that is the point where you stop paying for volume.
This is the test worth running before signing a packaging contract: take the dimensions of your three most used boxes and see which one lets actual weight win.
Does volumetric weight affect import duty?
It does, and indirectly. So the calculation matters to importers too, not only to whoever packs boxes for export. Freight enters the base on which entry taxes are assessed. Under Brazil's Customs Regulation, the customs value includes the cost of transport to the customs port or airport of discharge, the loading, unloading and handling charges up to that point and the insurance for the journey. Source: Decree No. 6,759/2009, article 77, as amended by Decree No. 11,090/2022.
If your supplier packs badly and freight rises because of volumetric weight, the tax base rises with it. The loss shows up twice on the same shipment: in transport and in tax. How that full calculation is built is covered in the guide to landed cost.
Ask suppliers for box dimensions before shipment, not just weight. Two suppliers quoting the same product price can carry very different delivery costs, purely because of the shape of what they send.
How do you reduce volumetric weight without risking the cargo?
By cutting the empty space, never the protection. A box packed too tight causes damage, and damage costs more than freight.
Adjustments that work in practice:
- pick the box to fit the product, not the box left over in the stockroom;
- cut down and refold boxes that are too tall, bringing the height to the contents;
- swap bulky void fill for thinner, denser protective material;
- take apart whatever comes apart and nest the pieces;
- consolidate orders for the same customer into one piece when the deadline allows;
- standardise two or three box sizes and measure the volumetric weight of each one once.
Step by step guidance on protecting, sealing and labelling is in the guide to packing a parcel. For cargo above 70 kg per piece, the logic shifts to palletising and handling equipment, the subject of the guide to heavy freight shipping.
Frequently asked questions about volumetric weight
Length times width times height, in centimetres, divided by 5,000, for each piece in the shipment. The result comes out in kilos and is compared with the actual weight.
They are. Volumetric weight, dimensional weight and cubed weight all name the same calculation, which converts the space occupied by cargo into kilos for billing purposes.
Billing weight is rounded up to the next 0.5 kg up to 30 kg, and to the next 1 kg above 30 kg. Each piece in the shipment is also rounded up to the next 0.5 kg.
It does, and the calculation runs piece by piece. Add the volumetric weights of every piece and compare that total with the sum of the actual weights to see which one is billed.
Because every shipment is reweighed and remeasured at the terminal. If the verified dimensions produce a volumetric weight higher than the one declared, billing follows the measured figure.
Sources
Measure first, pay for what the box holds
Volumetric weight is the one international freight variable you control on your own, with no dependence on routes, exchange rates or calendars. Measuring boxes and standardising two or three formats usually saves more than any attempt to renegotiate a rate table.
If you want billing weight under control and visibility over every piece from collection to delivery, open a DHL Express business account and ship with dimensions verified from the very first consignment.
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