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Volumetric weight calculator — dimensional weight for parcels

What volumetric weight is

Volumetric (or dimensional, "dim") weight converts the space a parcel occupies into kilograms. A light but bulky box — pillows, toys, packaged electronics — takes the place of a heavy one in the van, so carriers charge for that space. One volumetric kilogram is billed like one real kilogram.

The formula

Volumetric weight (kg) = Length (cm) × Width (cm) × Height (cm) ÷ divisor

The divisor depends on the carrier:

Example: a 40 × 30 × 20 cm box → 24,000 cm³ → 4.8 kg at 5000, 8 kg at 3000. The same box can cost nearly twice as much under a 3000 divisor, so use the one in your rate card. In inches the equivalent divisor is usually 139 (in³/lb).

Chargeable weight

The carrier compares two figures — the calculated volumetric weight and the actual weight on the scale — and bills the greater one. An 8 kg volumetric box weighing 5 kg is billed at 8; the same box weighing 12 kg is billed at 12. The tool labels each parcel "volumetric" or "actual" so you can see which applies.

Several parcels

For a multi-parcel shipment, work out the chargeable weight of each parcel and add them up; you do not add the volumetric weights first and compare the total with the total actual weight. The parcel list in the tool does exactly this: one billable figure per line and the shipment total underneath.

Lowering the bill

Because the calculation uses the outer dimensions of the box, empty space costs money. Choose a box close to the product's size, fold what folds, and combine small items into one parcel. Most rate cards price in weight bands (0–1, 1–2, 2–5, 5–10 kg …), so shaving half a kilogram can drop you into a cheaper band.