No ruler to hand? An A4 sheet of paper is 297 × 210 mm, so you can use one as a rough guide.
Dimensional weight and volumetric weight are two names for the same thing. Couriers in the US tend to say "dimensional weight" and couriers in the UK and Europe, including DHL, tend to say "volumetric weight", but the calculation is identical. It is a way of pricing a parcel by the space it takes up on a vehicle rather than by how heavy it is.
When you ship a parcel, the courier works out both its actual weight and its volumetric weight, then charges you for whichever is larger. This stops a large but light box, a duvet for example, from travelling at the price of a small heavy one. If your parcel is dense, you pay actual weight. If it is bulky and light, you pay volumetric weight.
Every major international courier uses the same formula. You multiply the three dimensions in centimetres to get the volume, then divide by the courier's divisor:
(Length cm × Width cm × Height cm) ÷ Divisor = Volumetric weight in kg
DHL, FedEx, UPS and TNT all use a divisor of 5000 for international shipments measured in centimetres. Evri/Hermes uses 4000, which makes its volumetric charges higher for the same box. A smaller divisor means a higher volumetric weight, so it costs you more.
Say you are sending a 40 cm × 30 cm × 20 cm box that actually weighs 2 kg. The volume is 40 × 30 × 20 = 24,000 cm³. Divide that by 5000 and you get a volumetric weight of 4.8 kg. The courier charges you for 4.8 kg, not 2 kg, because the box is bulky for its weight. If the same box weighed 6 kg, you would be charged for 6 kg instead, because actual weight is now the larger of the two.
If your courier quotes in inches and pounds, the US domestic version of the formula divides cubic inches by 139 instead. The calculator above handles the centimetre version, which is what UK and international shippers need.
Source: the 5000 divisor and volumetric weight method are published in the official guidance from DHL, FedEx and UPS. Verified May 2026.
DHL Express uses the term volumetric weight and applies a divisor of 5000 to shipments measured in centimetres. So a DHL parcel measuring 50 × 40 × 30 cm has a volume of 60,000 cm³, which divided by 5000 gives a volumetric weight of 12 kg. DHL compares that against the actual weight and bills the higher figure. This is why a DHL quote can come back far above what your kitchen scales told you: the box is being priced on its size. To bring a DHL charge down, the only lever is a smaller box, because the divisor is fixed.
FedEx applies the same 5000 divisor to international shipments measured in centimetres, so the calculation matches DHL's. The one difference to watch is FedEx domestic services inside the US, which divide cubic inches by 139 and quote in pounds. For UK senders posting internationally with FedEx, use the centimetre formula and the 5000 divisor, which is what this calculator does.
UPS also uses a divisor of 5000 for international centimetre measurements, identical to DHL and FedEx. As with FedEx, the US domestic UPS rate uses the 139 cubic-inch divisor, but for international parcels from the UK the 5000 figure is the one that applies. UPS rounds part-kilograms up to the next half or whole kilogram on some services, so treat the calculator result as the floor of what you will be charged, not the exact penny.
Your package's dimensional weight exceeds its actual weight. Couriers charge for whichever is larger to prevent customers from sending light items in huge boxes, which wastes vehicle space.
No. Royal Mail uses fixed format categories (Letter, Large Letter, Small Parcel, Medium Parcel) instead of dimensional weight. They don't charge based on how much space your item takes up.
Most major international couriers (DHL, FedEx, UPS, TNT) use 5000. Evri/Hermes uses 4000. Always check your courier's website or shipping software for the exact rate card.
Yes, they are the same calculation under two names. "Volumetric weight" is the term DHL and most UK and European couriers use; "dimensional weight" is the more common US term. The formula and the result are identical.
DHL multiplies length × width × height in centimetres and divides by 5000 to get the volumetric weight in kilograms. It then charges you for whichever is greater, the volumetric weight or the actual weight. A 50 × 40 × 30 cm box works out at 60,000 ÷ 5000 = 12 kg.
For international shipments measured in centimetres, FedEx and UPS both use 5000, the same as DHL. Their US domestic services use a different formula that divides cubic inches by 139, but that does not apply to parcels sent from the UK.
Multiply the three sides in centimetres to get the volume in cubic centimetres, then divide by your courier's divisor, usually 5000. For example, 30 × 25 × 20 = 15,000 cm³, and 15,000 ÷ 5000 = 3 kg volumetric weight.
Generally no, dimensional weight is a standard industry practice used by all major couriers for large, light items. It's disclosed in their terms. The best strategy is to pack more efficiently.
This calculator uses the standard dimensional weight formula. However, couriers may apply rounding rules, minimum charges, or special handling fees that won't show here. Always verify with your courier's rate card before shipping high-value items.