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.
What this calculation does—and does not include.
Included in this model
- Actual vs dimensional weight
- Metric and imperial dimensions
- Editable dimensional divisor
- Billable-weight comparison
Not automatically included
- Carrier-specific rounding rules not entered
- Zone/fuel/surcharge pricing
- Contract-specific divisors
- A shipping-price quote
Formula utility — divisor is editable
Reviewed 2026-08-23. Review dates describe the live model, not a guarantee that a third-party fee has not changed since.
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.
Questions this calculator is designed to answer.
dimensional weight calculator
Enter package dimensions, actual weight and your carrier divisor to compare dimensional and scale weight.
See common box examples →free dimensional weight calculator
Use metric or imperial units and keep the divisor editable because carrier services and contracts can use different rules.
Compare package sizes →calculate dimensional weight in cm
For metric inputs, multiply length by width by height and divide by the service-specific divisor, then compare the result with actual weight.
See the dimensional-weight formula →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.