Find the dimensional-weight break-even point
If dimensional weight is above scale weight, the package is paying—in rating terms—for space rather than mass. The mathematical break-even packed volume is actual weight in kg × dimensional divisor in cubic centimetres. At that volume, actual weight and dimensional weight are equal under the selected divisor.
Worked example: 60 × 40 × 40 cm, 8 kg
The current carton volume is 96,000 cm³. At a 5,000 divisor, its dimensional weight is 19.2 kg. An 8 kg package reaches break-even at 40,000 cm³, so the theoretical volume reduction required is about 58.3%.
If length and width stayed fixed at 60 × 40 cm, the equivalent target height would be about 16.7 cm. That is a mathematical threshold, not a recommendation that the product can safely be packed into a 16.7 cm-high box.
What “packaging efficiency” means here
This tool focuses narrowly on dimensional-weight efficiency. It does not judge whether a carton is environmentally optimal, strong enough, fast to pack, suitable for automation or compliant with a retailer's packaging specification. A packaging change is useful only if it still protects the product and works operationally.
Reducing the right dimension
Because DIM weight is based on length × width × height, reducing any outer dimension lowers volume. In practice, however, not every dimension is equally flexible. A rigid product may fix length and width while allowing excess headroom to be removed. The calculator therefore reports the total volume reduction required, while the result message also shows the theoretical height target if length and width remain unchanged.
When carton redesign will not reduce DIM charges
If actual weight is already greater than dimensional weight, the package is weight-limited under the selected divisor. Reducing carton size can still improve pallet or container utilisation, but the simple actual-vs-DIM comparison will not fall below the scale weight. Likewise, changing to a carrier/service with a different divisor can change the threshold without changing the box at all.
Use shipment-level optimisation for multiple SKUs
The main Shipment Workspace Packaging Optimiser ranks mixed SKUs by the DIM-weight overhead they create. If you add an indicative freight rate per chargeable kilogram and annual shipment frequency, it can also show which carton changes have the largest theoretical cost impact—useful for deciding where packaging-development effort should start.
Continue planning the shipment
Shipment Workspace
Enter mixed cargo once and carry the same data through volume, chargeable weight, pallets, containers and freight costing.
Methodology & sources
See the formulas, planning assumptions, source links and review dates behind ShipMeasure.
Packaging efficiency
Find the carton-volume threshold where dimensional weight stops exceeding actual weight.