If you have ever paid to ship a light but bulky parcel and been charged for a much heavier weight, you have met dimensional weight. Carriers use it so that large, light parcels pay for the space they take. This guide explains what dimensional weight is and how it is calculated, with our free Dimensional Weight Calculator.
The idea
Planes and trucks fill up by space as well as weight. A large box of pillows weighs little but takes as much room as a heavy box of books. Dimensional (DIM) weight converts a parcel’s volume into an equivalent weight.
The formula
DIM weight = Length × Width × Height ÷ DIM divisor
| Units | Common divisors |
|---|---|
| cm and kg | 5,000 (most international couriers), 6,000 (air freight and some services) |
| inches and lb | 139 (common for US carriers), 166 (some services) |
Chargeable weight
Carriers charge the higher of actual weight and DIM weight.
| Parcel | Actual weight | DIM weight (÷5000) | Charged |
|---|---|---|---|
| 40 × 30 × 20 cm pillows | 1.5 kg | 4.8 kg | 4.8 kg |
| 30 × 20 × 15 cm books | 6 kg | 1.8 kg | 6 kg |
Rounding
Most carriers round dimensions up to the next whole cm or inch, and round chargeable weight up to the next 0.5 kg or 1 lb.
Inches example
A box of 16 × 12 × 10 in with divisor 139: 1,920 ÷ 139 = 13.8, rounded up to 14 lb.
Why divisors differ
A lower divisor gives a higher DIM weight. Divisors depend on the carrier, service and contract; large shippers sometimes negotiate higher divisors.
Domestic couriers in Pakistan
Local courier services also apply volumetric rules for larger parcels, often using a divisor of 5,000. Check each courier’s rate card. Read volumetric weight with couriers in Pakistan.
Reducing DIM weight
Use smaller boxes and less empty space; see DIM divisors compared and the Box Size Calculator. For total charges, use the Shipping Cost Calculator.
Frequently asked questions
What is dimensional weight?
A weight calculated from a parcel’s volume, used when it is higher than actual weight.
What divisor do couriers use?
Commonly 5,000 for cm and kg, or 139 for inches and pounds.
Which weight do I pay for?
The higher of actual weight and dimensional weight.