Free tool
Dimensional weight calculator
Carriers bill the greater of your package's actual weight and its volumetric (DIM) weight. Enter the dimensions and weight to see exactly what you'll be charged on — before you ship.
Package details
Your billable weight will appear here
Enter the package dimensions and actual weight to see the dimensional and billable weight.
How dimensional weight works
A box of pillows and a box of bricks take up the same space on a truck or plane, but the pillows weigh far less. To price for the space a package occupies — not just its mass — carriers calculate a dimensional weight and bill you on whichever is higher: actual or dimensional.
The formula
Dimensional weight = (Length × Width × Height) ÷ DIM divisor
Billable weight = the greater of actual and dimensional weight, rounded up.
Common DIM divisors
| Carrier / standard | Units | Divisor |
|---|---|---|
| UPS / FedEx — US domestic | inches / lb | 139 |
| UPS / FedEx / DHL — international | cm / kg | 5000 |
| Air freight (IATA standard) | cm / kg | 6000 |
| USPS oversize / legacy | inches / lb | 166 |
Divisors vary by carrier, service level, and contract — always confirm the divisor in your carrier agreement. This tool is an estimate to help you plan and compare.
What is dimensional (volumetric) weight?
Dimensional weight — also called volumetric weight or DIM weight — is a pricing technique carriers use for light, bulky packages. Instead of charging only by actual weight, they charge by the package volume divided by a fixed number (the DIM divisor). You pay whichever is greater: actual weight or dimensional weight.
How do I calculate dimensional weight?
Multiply length × width × height to get the volume, then divide by the carrier’s DIM divisor. In inches and pounds, most US carriers use 139 (so DIM lb = L×W×H ÷ 139). In centimeters and kilograms, couriers typically use 5000 and air freight uses the IATA standard of 6000.
Which weight am I actually billed on?
The greater of your actual weight and the dimensional weight, rounded up to the next whole pound or kilogram. If your package is large but light, you are usually billed on dimensional weight.
How can I reduce dimensional-weight charges?
Use the smallest box that safely fits the contents, remove excess void fill, and avoid oversized cartons. Even a small reduction in box size can drop you below the dimensional-weight threshold and lower your bill.