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Volumetric Weight Calculator

Enter carton dimensions, piece count and actual weight to get the volumetric weight, then compare it with the actual weight: the greater of the two is the chargeable weight. Courier, air and sea conventions are all supported, computed locally.

A parcel that weighs three kilograms but ships at twenty is not a billing error. Cargo space is scarcer than payload, so carriers convert the space a parcel occupies into a weight, compare it with the actual weight, and charge whichever is greater.

The divisor differs by service: courier tariffs commonly use 5000, air freight 6000, and sea freight converts one cubic metre to 1000 kilograms. Loose packing and extra filler raise the volumetric weight and the freight bill with it, which is why forwarders keep asking for tighter packaging. This tool runs all three conventions side by side so you can see where the savings are.

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How to use

  1. Measure the carton length, width and height in cm, then enter the piece count and total actual weight in kg.
  2. Choose the convention: courier ÷5000, air ÷6000, or sea at 1 m³ = 1000 kg.
  3. Read the volumetric weight, the actual weight, and which one is charged.
  4. If the volumetric weight is charged, try shrinking the carton: the figure falls in proportion.

How it works

Where volumetric weight comes from

Volumetric weight converts the space a parcel occupies into a weight using a fixed divisor: length x width x height / divisor. Space and payload are both limited on any vehicle, so a bulky but light parcel such as a cushion or a box of clothing wastes capacity; carriers use volumetric weight to price that space fairly, then charge the greater of the two figures.

Why the divisor differs by service

The divisor reflects the balance of space and payload on each service. Courier vans are payload-limited with tight space, so 5000 is common (one kilogram per 5000 cm³); air cargo space is more precious, so 6000 appears often; sea freight converts one cubic metre to 1000 kilograms. The same carton can be charged completely differently across services, so always confirm the divisor before booking.

How to bring volumetric weight down

Because volumetric weight depends only on carton dimensions, the fix is straightforward: use a tighter carton, cut filler, vacuum-compress what can be compressed and split oversized boxes into several well-fitted ones. Shortening any single dimension reduces the volumetric weight in proportion, usually with more effect than negotiating a discount.

Code example

JavaScript Volumetric and chargeable weight (the greater one, not the sum) 

// volumetric weight converts occupied space into weight, dimensions in cm
const volWeight = (l * w * h) / 5000;       // courier 5000, air 6000
const chargeable = Math.max(volWeight, actualWeight);

// a 60 x 40 x 40 cm carton: 96000 / 5000 = 19.2 kg
// actual weight is only 5 kg, but 19.2 kg is what gets charged

Python Three conventions and the chargeable-weight test 

DIVISOR = {"express": 5000, "air": 6000}

def chargeable_weight(l, w, h, actual_kg, mode="express", cartons=1):
    vol = l * w * h / DIVISOR[mode] * cartons
    return {"vol": round(vol, 3),
            "charged": round(max(vol, actual_kg), 3),
            "by": "volume" if vol > actual_kg else "actual"}

chargeable_weight(60, 40, 40, 5)      # 19.2 kg, charged by volume
chargeable_weight(30, 20, 20, 20)     # 2.4 vs 20 -> charged by actual weight

FAQ

What is the difference between volumetric weight and actual weight?

Actual weight is what the scale reads; volumetric (dimensional) weight is the space the packaging occupies, converted to a weight. Carriers charge whichever is greater, so light and bulky shipments are usually billed on volumetric weight while dense cargo is billed on actual weight.

Is courier freight divided by 5000 or 6000?

It depends on the carrier and service: international express commonly uses 5000, some air freight agents use 6000, and discounted services may use 8000. The difference is significant on the same shipment, so ask which divisor applies and switch the convention here before comparing quotes.

How is volumetric weight calculated for sea freight?

Sea freight typically converts one cubic metre to 1000 kilograms and compares that with the actual weight. Full container loads are usually charged per container rather than by volume, while LCL is charged on volume or equivalent weight; a few lanes use ratios such as 1:167, so check the carrier's rule.

Why does my figure differ from the forwarder's?

Three common reasons: a different divisor (5000, 6000 or 8000); rounding rules, since some carriers round dimensions up to whole centimetres and the result up to 0.5 or 1 kg; and minimum chargeable weights or light-cargo coefficients on some services. Treat this tool as an estimate and the invoice as the reference.

How can I reduce volumetric weight?

Shrink the carton: remove empty space, cut filler, vacuum-compress soft goods and split oversized boxes into fitted ones. Shortening any dimension reduces the figure proportionally. Do not sacrifice packaging strength to gain a few centimetres - damage costs far more than the freight saved.

Is chargeable weight the volumetric weight plus the actual weight?

No, it is the greater of the two, not the sum. With 19.2 kg volumetric and 5 kg actual, the chargeable weight is 19.2 kg; with 30 kg actual and 19.2 kg volumetric it is 30 kg. Adding them would seriously overstate the freight cost.

Does volumetric weight apply to every transport mode?

Most modes use a similar mechanism with different conventions: express and air freight use 5000 or 6000, LCL sea freight prices by volume, FCL by container, and road or multimodal services use comparable rules. Carriers' terms govern, and this tool covers the three most common conventions.

Are my dimensions and weights uploaded?

No. All calculations happen in your browser, so dimensions, weights and piece counts never leave your device, and the tool works offline.