Use the output as a threshold, not a forecast.
Carriers often charge for the space a parcel occupies rather than scale weight alone. Dimensional, volumetric or cubed weight converts package volume into a comparable weight using a service-specific divisor.
This calculator deliberately leaves the divisor editable. Published retail rules, negotiated contracts, domestic services and international services can use different divisors and rounding rules, so a hard-coded universal number would be misleading.
Dimensional weight formula
Dimensional weight equals length multiplied by width multiplied by height, divided by the carrier divisor. Billable weight is the greater of dimensional and actual weight for each package.
Total billable weight multiplies the per-package result by the number of identical packages. A carrier can rate packages individually, round every dimension upward or apply minimums and surcharges after this calculation.
A 40 × 30 × 20 cm parcel has 24,000 cm³ of volume. With a 5,000 divisor, its dimensional weight is 4.8 kg, so a 3 kg physical parcel may be billed at 4.8 kg before rounding.
Limitations to keep visible
- Confirm the divisor, rounding and unit conventions for the exact carrier product and account contract.
- This tool does not estimate zones, fuel, remote-area, peak, oversize or additional-handling surcharges.
- Measure the packed outer carton, not the product dimensions.
Frequently asked questions
What divisor should I use?+
Use the divisor published for your exact carrier, service and unit system. Common examples are only defaults and contracts may differ.
Why is billable weight higher than scale weight?+
The package occupies more transport capacity than its physical mass suggests, so the carrier rates the dimensional weight.
Do carriers round dimensions?+
Many do. Apply the carrier's specified rounding before entering dimensions when you need an invoice-level estimate.