Container Loading Calculator — 20 ft, 40 ft & High Cube
Calculate geometric carton capacity for standard or custom containers — including rotations, door clearance and payload.
Example: 400 × 300 × 250 mm cartons in a 40 ft High Cube
For the PackMize 40 ft High Cube preset, with all rotations allowed, zero clearance, 3000 cartons available and 8 kg per carton, PMZ-CONTAINER 3.6.0 finds 2486 cartons and 19,888 kg of cargo. This is a best-found geometric plan, not a universal container capacity or a loading-sequence guarantee. Changing dimensions, orientation or payload can change the result.
Planning a complete shipment?
Keep this single-SKU calculator free. For mixed products, import the order, compare container scenarios and generate a reusable load plan.
How the container loading calculator works
PackMize generates all box orientations allowed by the selected rotation axes, builds efficient two-dimensional layer patterns for each feasible layer height, and then chooses a height combination that maximizes the number of boxes inside the container. Payload and requested quantity are applied after geometric capacity.
Container dimensions are not universal
Internal and door dimensions can vary slightly by container manufacturer, owner and equipment series. PackMize therefore treats its presets as representative planning dimensions and exposes a custom-container option for operational use.
PackMize publishes the external equipment references used to document this assumption, including Hapag-Lloyd 20 ft and 40 ft High Cube specifications, on the sources page. Carrier examples are reference points, not a claim that every container has identical dimensions.
Limitations
This single-SKU calculator models rigid rectangular cartons and does not itself perform delivery-stop sequencing, cargo-balance analysis, axle-load calculations, lashing, crush-strength modelling, dangerous-goods segregation or full forklift-access simulation. For mixed products, stop-order auditing and geometric cargo CoG/balance diagnostics, use the PackMize Multi-SKU Load Planner. A geometric plan is not a transport-safety approval.
Frequently asked questions
Does the container calculator use cubic metres only?
No. It builds geometric layers from the carton dimensions and tests allowed orientations before applying payload limits.
Are standard container dimensions exact for every carrier?
No. Published internal and door dimensions can vary by manufacturer and equipment. PackMize presets are representative and can be replaced with custom dimensions.
Can I load multiple product sizes?
The free calculator optimizes one rectangular SKU at a time. For several product sizes and order quantities, use the PackMize Multi-SKU Load Planner in the professional workspace.
How do I keep cartons upright?
Choose Keep carton upright under Carton handling. PackMize will keep the carton height vertical while still allowing a 90-degree turn on the floor.
Can I calculate palletized container loads?
The free tool places identical cartons directly inside a container. It does not calculate the packing of fully loaded pallets or combine different product sizes.