Carriers do not only weigh your parcel — they measure it. This volumetric weight calculator applies the standard dimensional-weight formula, length × width × height ÷ divisor, with the three divisors the industry actually uses: 5000 for international air services such as DHL, FedEx and UPS, 6000 for many air and economy products, and 4000 for road and regional couriers. It then compares the result with the weight on your scale and reports the billable weight — the higher of the two — including the round-up to the next half kilo most carriers apply before pricing.
The formula, and why the divisor changes
Volumetric weight = (length × width × height) ÷ divisor, with all measurements in centimetres giving kilograms. The divisor is a density threshold in disguise: at 5000, a cubic metre of parcel “should” weigh 200 kg; anything lighter for its size is charged as if it were denser, because aircraft and vans run out of space before they run out of lifting capacity. Express services flying parcels internationally settled on 5000; slower air and economy products often use 6000, which is kinder to bulky goods; road networks and many Latin American and regional couriers use 4000, which is harsher. The same box can therefore carry three different billable weights on three different services — which is why this calculator makes the divisor a choice, not a constant, and lets you enter a custom one if your carrier publishes something else (some use 7000 for sea freight or domestic economy).
Worked example
A 40 × 30 × 20 cm box weighing 3 kg on the scale: volume is 24,000 cm³, so at divisor 5000 the volumetric weight is 4.8 kg. The scale says 3 kg, the tape measure says 4.8 kg — you are billed for 4.8 kg, and after the usual round-up, for 5 kg. Switch the divisor to 4000 and the same box grades at 6 kg volumetric. Nothing about the parcel changed; the service did. In inches the maths is identical after conversion: a 10 × 10 × 10 inch cube is 16,387 cm³, which grades at 3.28 kg volumetric at 5000 — this calculator converts for you when you toggle the units.
How to pay less, honestly
You cannot argue with the formula, but you can feed it better numbers. Use the smallest box that protects the product: cutting 5 cm off the height of the example box drops its volumetric weight from 4.8 to 3.6 kg. Compress soft goods (vacuum bags for textiles are the classic case). Measure the closed, packed box — carriers measure the bulging outside, not the catalogue dimensions of the empty carton, and their laser scanners re-measure at the hub, so optimistic measurements become “weight correction” surcharges. And when a product is dense and small, check whether a service pricing purely on actual weight beats the volumetric services for that shipment.
Volumetric weight — frequently asked questions
Which divisor does my carrier use? 5000 for most international express air (DHL, FedEx, UPS), 6000 for many economy air products, 4000 for numerous road and regional couriers. Your carrier’s tariff page is the authority for your contract — enter it as a custom divisor if it differs.
Do carriers really round up? Yes: the common convention is up to the next 0.5 kg (some round to the next whole kilo or 100 g). The last row of the result applies the half-kilo convention so the estimate matches the invoice.
What if the parcel is an odd shape? Carriers measure the smallest rectangular box that would contain it — length is the longest side, and bulges count. Measure your parcel the same way.
Is volumetric weight used for letters and documents? Rarely: documents in flat envelopes are normally priced on actual weight. The formula targets parcels, where space is the scarce resource.
Related tools
Versión en español: Calcular Peso Volumétrico de Paquetes: Divisor 5000, 6000 o 4000 y Peso Facturable · Volumetric weight for Chilexpress (in Spanish) · Volumetric weight + packaging cost (in Spanish).
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