Dimensional Weight Calculator

About this calculator

Dimensional weight and volumetric weight are the same calculation. US and international carriers say "dimensional" or "DIM weight"; Indian couriers say "volumetric". Both mean the parcel's size expressed as a weight, and both exist because a van fills up before it weighs too much.

This page uses the international vocabulary. If your rate card says volumetric, the volumetric weight calculator is the same arithmetic with the labels you are used to.

How to use this calculator

1. Measure the packed carton at its widest points, including tape and bulges.
2. Enter the three dimensions and the unit you measured in.
3. Enter the DIM divisor from your carrier's tariff. It is service-specific.
4. Add the actual weight if you know it, to see which figure you will be billed on.

The formula

Volume            = Length x Width x Height   (centimetres)
Dimensional weight = Volume / Divisor         (kilograms)
Chargeable weight  = greater of dimensional and actual

A divisor is a density assumption. 5000 means the carrier treats 5,000 cubic centimetres as one kilogram. A smaller divisor produces a larger billed weight, so a 4000 service is 25% more expensive for the same carton than a 5000 one before you compare rates at all.

Carriers quoting in inches and pounds publish divisors on a different scale — 139 and 166 are the common ones. Those are not interchangeable with 4000 and 5000. Convert your dimensions to centimetres and use the metric divisor, or use the carrier's own imperial formula; do not mix the two.

Worked example

A 40 × 30 × 20 cm carton weighing 4 kg, on a service using 5000:

Volume      = 40 x 30 x 20  = 24,000 cm³
Dimensional = 24,000 / 5000 = 4.8 kg
Chargeable  = max(4.8, 4)   = 4.8 kg

The carton is billed at 4.8 kg though it weighs 4 kg. On a 4000 divisor it would be 6 kg.

Notes and limits

• The divisor belongs to the service, not the company. One carrier can use three.
• Imperial divisors (139, 166) and metric divisors (4000, 5000, 6000) are different scales. A number from one cannot be used with the other.
• Volume is the product of three numbers, so trimming each dimension by 10% cuts the dimensional weight by about 27%.
• Air freight normally uses 6000, which is why the same carton is cheaper by air freight weight than by express courier weight.

What this calculation assumes

• Dimensions are of the packed carton, including packaging.
• The divisor entered is the one for the specific service being used.
• No rounding is applied unless the selected courier has a rounding rule configured.