Two suppliers can quote the same charger at the same unit price and produce very different landed costs, because landed cost is driven by how the product is packed rather than what it contains.
Master carton dimensions
Start with the pallet, not the carton. A pallet is 1200 by 1000 millimetres in most of the world (or 1200 by 800 in parts of Europe), and a carton that does not divide evenly into that footprint leaves usable space on every pallet for the whole shipment. Ask what the carton’s footprint is and how many fit per layer.
Units per carton
Increasing units per carton reduces board and handling per unit but increases weight. The sweet spot is usually where the carton stays under the manual-handling limit and still fills the pallet footprint. A change from 50 to 60 units per carton is worth doing if it does not push the weight past what a warehouse will lift.
Pallet height and container loading
Container internal height is fixed, so the pallet stack height decides how many pallets fit. A few centimetres per pallet multiplied across a shipment is real money. The same logic applies inside the carton: air is the most expensive material you can ship.
Packaging that survives the journey
Optimising volume only pays if the cartons arrive intact. The order of decisions is: board grade for the drop, structure for the stacking load, then volume. Cutting the board to save a centimetre and losing a pallet to crushed corners is a net loss, and it is the most common way packaging optimisation goes wrong.
What to ask for
Four numbers per SKU: master carton dimensions, units per carton, cartons per pallet, and gross weight per carton. A supplier who can send those in the quotation is a supplier who has already done this work. If they cannot, ask them to do it before the first booking — it is usually a drawing change, not a tooling change.