Two capacities, and the one that binds decides everything
Every load has a space capacity and a weight capacity. Space capacity is floor positions times tiers. Weight capacity is the payload limit divided by what one unit weighs. The load is whichever of those is smaller, and which one it is changes what you should do about it.
When weight binds, the container is part empty and building a taller pallet gains you nothing. The lever is density: fewer pounds per unit, or mixing dense freight with light freight in the same load so the average comes down. When space binds, the container is at its legal weight nowhere near, and the lever is cube: a shorter pallet, a tighter carton, a footprint that leaves less remainder on the floor.
People routinely optimise the wrong one. A team spends a month redesigning cartons to gain four percent of cube on a lane where the weight limit was already the binding constraint, and nothing changes on the invoice. The first thing to establish is which number is smaller.
Floor positions are a packing problem, not a division
Dividing interior length by pallet length and interior width by pallet width gives one answer. Turning the pallet gives another. Mixing the two within the same floor gives a third, and it is often the largest. This calculator searches all three, the same way the pallet load planner searches layer patterns, and shows you the blocks so you can judge whether the arrangement is workable in practice.
Two practical caveats. A mixed floor plan takes longer to build and is harder to unload in order, which matters if the load has multiple stops. And the search here is not exhaustive, so treat the number as a good arrangement rather than a proven ceiling.
The measurements that go wrong
| Measurement | Common mistake | Consequence |
|---|---|---|
| Interior length and width | Using the nominal size of the equipment | Nominal sizes are exterior. Interiors run smaller and vary between units. |
| Interior height | Ignoring what hangs from the ceiling | Lighting, ducting and rails eat inches exactly where the top tier goes |
| Door opening height | Assuming it matches the interior | A unit that fits inside will not go through the door |
| Unit height | Measuring the pallet before it is wrapped | Wrap, slip sheets and a domed top layer all add height |
| Payload limit | Taking the number from a specification sheet | The allowed payload depends on the equipment, the route and what else is on it |
None of these are numbers to assume. Every one of them is an input in this calculator for the same reason: they differ between one piece of equipment and the next, and the only reliable source is whoever is supplying it.
Utilisation is a diagnostic, not a target
The volume figure tells you what share of the box is product. A low number is not automatically a failure. If the freight is dense and weight binds, low volume utilisation is the correct outcome and chasing it wastes effort. If the freight is light and space binds, a low number is money and it is worth attacking, usually at the package rather than at the load plan.
Read the utilisation line alongside the binding constraint line, never on its own. The pair together tells you which of the two levers is available, and that is the only thing the number is good for.
When the shipment moves as loose pallets rather than a full load, the number that decides the bill is density rather than positions, and that calculation is over at the freight density calculator. If you are moving household goods rather than freight, the moving truck size calculator and the trailer load planner handle the same geometry with different inputs.
Questions people ask
Why does the calculator ask me for the interior dimensions instead of knowing them?
Because there is no single answer to give. Equipment of the same nominal description differs in interior length, width and height between builds, between owners and between how it has been repaired, and door openings differ from interiors on the same unit. A calculator that hard-coded a number would be wrong often enough to be dangerous, and it would go stale. Measure the unit you are using, or get the interior dimensions from the party supplying it, and enter those.
What is the difference between floor loading and palletising?
Floor loading means stacking cartons directly, with no pallet under them, which uses the cube far better because you are not shipping pallets or the air above a partly filled one. It costs a great deal more labour at both ends, since every carton is handled individually instead of a whole pallet moving at once. The trade is usually cube against labour hours, and it flips depending on wage rates, how far the freight travels and whether the receiver can even accept floor loaded freight. You can model either here by entering a single carton as the unit rather than a loaded pallet.
Should I stack pallets two high?
Only if the product and the packaging support it, which is a question for the carton specification rather than the load plan. The bottom pallet takes the entire weight of the top one through its own top layer, which is the layer least built to carry it. Where double stacking works it can nearly double the load, so it is worth testing properly rather than assuming either way. Where it does not, a crushed bottom layer costs more than the freight saved.
How much clearance should I leave above the top tier?
Enough that the unit goes in and comes out without catching, which in practice means more than the arithmetic suggests. A loaded pallet is not perfectly flat on top, wrap adds a little, forks need to tilt slightly to place and to lift, and floors are not level. The default here is two inches and that is a starting point rather than a recommendation. If loads are catching on the way in, the clearance is the first number to raise.
Does this account for weight distribution across axles?
No. It gives you how many units fit and what they weigh in total, which is a different question from where that weight sits. Axle loading depends on where along the deck each unit is placed, and a load that is legal in total can be over on one axle. If that is the constraint you are working with, the trailer axle load calculator covers it, and for anything regulated the governing weight rules come from the authority for the route rather than from any calculator.