Dimensional Weight Formula
The dimensional weight formula is package volume divided by a carrier DIM divisor. It turns the space occupied by a parcel into a comparable pricing weight.
The formula
Use outside dimensions of the packed parcel. Keep all three dimensions in one unit system and choose the corresponding divisor. Carrier instructions may require dimensions or final weight to be rounded at specific stages.
Imperial worked example
A 12 × 12 × 12 inch carton has 1,728 cubic inches. At divisor 139, its raw dimensional weight is 12.43 lb. At 166, it is 10.41 lb. If actual weight is 9 lb, dimensional weight is greater in both examples before carrier rounding.
Metric worked example
A 40 × 30 × 20 cm carton has 24,000 cm³ of volume. At factor 5000, it produces 4.8 kg. At 6000, it produces 4 kg. If scale weight is 6 kg, actual weight is greater.
Why the divisor matters
The divisor represents how much package volume corresponds to one unit of pricing weight. A lower divisor produces a larger result. It does not represent an exchange rate and it must match the units and carrier rule being used.
Frequently asked questions
What is a DIM divisor?
A DIM divisor converts package volume into dimensional weight. Its value depends on units and the applicable carrier rule.
What is billable weight?
Billable weight is the weight used to rate a shipment, commonly the greater applicable actual or dimensional weight, subject to carrier rules.
Can I mix inches with factor 5000?
No. Use inches with an imperial divisor and centimeters with a metric divisor unless your carrier explicitly defines another calculation.