DIM weight · volumetric weight · billable weight
Enter package dimensions, actual weight and your carrier divisor. See the dimensional weight, which number you are billed on, and the shipment total.
Divisors are cubic inches per pound. Carriers round each dimension to the nearest whole inch and round the result up to the next whole pound.
Trailers and aircraft run out of space long before they run out of weight capacity. Dimensional weight — DIM weight, volumetric weight, cubed weight, all the same thing — is how carriers charge for the space a light, bulky package takes up.
The formula is one division: L × W × H ÷ divisor. You are billed on whichever is larger, the dimensional weight or the actual scale weight. That larger number is the billable weight.
A smaller divisor means a higher dimensional weight and a higher bill. UPS and FedEx apply 139 to most US domestic accounts; retail and some published rates use 166. Air freight works in metric and uses 6000 cm³ per kg, which is the same ratio as 166 cubic inches per pound.
Your negotiated divisor is a real line item in a carrier contract and it is negotiable. Moving from 139 to 166 cuts the dimensional weight of every light package by about 16% without changing anything you ship.
Carriers round each measured dimension to the nearest whole inch before multiplying, then round the resulting weight up to the next whole pound. A package measured at 24.4 in bills as 24 in; at 24.6 in it bills as 25 in, and on a large box that single inch can cost a pound of billable weight.
| Service | Divisor | Metric equivalent |
|---|---|---|
| UPS / FedEx daily rates | 139 | 5000 cm³/kg |
| UPS / FedEx retail | 166 | 6000 cm³/kg |
| USPS (over 1 cu ft, zones 5–9) | 166 | 6000 cm³/kg |
| DHL Express | 139 | 5000 cm³/kg |
| Air freight (IATA) | 166 | 6000 cm³/kg |
Dimensional weight is a parcel and air freight concept. LTL freight does not use a divisor at all — it converts your shipment to pounds per cubic foot and reads a class off the NMFC density scale. If your shipment is palletized and moving LTL, the freight class calculator is the tool you want, not this one.