Container Load Calculator

Heavy cargo fills the payload, light cargo fills the space

A 20′ container holds roughly 33 cubic meters but carries close to 28 metric tons. Anything denser than about 850 kg per cubic meter hits the weight limit before it fills the box. Stone, tiles, machinery, fasteners, canned food and liquids routinely fill a 20′ only halfway up the walls.

That is why heavy cargo ships in 20′ boxes and light, bulky cargo ships in 40′ high cubes. You pay per container either way, so you want the limit you hit to be the one you are paying for.

For furniture, apparel, plastics, packaging and most consumer goods, space runs out first. Moving from a 40′ standard to a 40′ high cube often adds another tier of cartons for a modest difference in cost, and a 45′ high cube adds roughly 13% more cube again.

Getting more into the box

Small changes to carton size add up. A carton whose footprint divides evenly into the 2.35 m internal width wastes far less floor than one that leaves a 30 cm strip down the side. Taking a centimeter off carton height can add a whole tier. Try a couple of carton sizes in the calculator before you finalize packaging; it is the cheapest saving available to an importer.

If you won’t fill a full container, LCL consolidation prices per revenue ton instead, and the crossover is usually around 13–15 cubic meters. Work out your CBM and revenue tons with the chargeable weight calculator, then compare.

Payload, tare and the weight limits that really apply

Payload is the container’s maximum gross weight minus its tare, the weight of the empty box. Both numbers are stamped on the CSC safety-approval plate on the door and vary from one container to the next. Treat the figures in the specifications table as typical published values, not the limit for your specific container.

In practice, the container’s own payload is rarely what stops you. Road weight limits at origin and destination usually cap the load first. In the United States, the federal gross vehicle weight limit on the Interstate system often means a standard chassis and tractor can legally move only a fraction of a container’s rated payload without an overweight permit or a specialized chassis. Ports, rail ramps and some inland corridors set their own caps. Plan the load around the tightest leg of the route, not around the plate.

Verified Gross Mass (VGM) also applies. Under SOLAS, the shipper must declare the VGM (cargo plus dunnage plus tare) before the container can be loaded onto a vessel. Add the calculator’s loaded weight to the tare in the table for a working VGM estimate to check against the limit.

How many pallets fit in a container

A container is 2.35 m wide inside. That width takes two 40-inch pallet sides (2.03 m) or two 1,000 mm sides (2.00 m), but not two 48-inch or two 1,200 mm sides, so the pallet count depends on which way the pallets face. The usual plan runs one column of pallets lengthwise and one column turned: a 20′ takes 11 Euro pallets (7 turned beside 4 lengthwise) or 9 GMA 48 × 40 in pallets (5 turned beside 4 lengthwise); a 40′ or 40′ high cube takes 25 Euro or 20 GMA pallets; a 45′ high cube takes 27 Euro or 24 GMA. The pallets-per-container table above lists every preset and size.

Those counts are the geometric maximum with zero clearance. Where the slack is under a few centimetres (22 ISO 1200 × 1000 pallets in a 40′ leaves 32 mm along the length), expect to lose a pallet to overhanging stretch wrap, a bent deck board or a loader who cannot square the last row. Count on the figure minus one for a tight plan and ask the loading point how they stack before you commit to it.

Double stacking doubles the count only when two loaded pallets clear the internal height: 2.39 m in a standard box, 2.69 m in a high cube. Two 47-inch (1.20 m) pallets fit a high cube and not a standard 40′, which is the main reason palletized consumer goods ship in high cubes. The pallets on the bottom tier also have to carry the top tier, so the stack is limited by the cartons, not the container.

How the estimate is calculated

The calculator tries all six ways a rectangular carton can sit square to the container walls and keeps the one that fits the most. For each, it divides the container’s internal length, width and height by the matching carton dimension, rounds each result down to a whole number, and multiplies the three together.

That gives a floor-loaded block with every carton the same way up. It does not mix orientations, rotate end rows, or allow for pallets, dunnage, airbags, bulkheads or lashing. It is deliberately not a 3D bin-packing solver. Real stuffing plans usually come in a few percent below the geometric number once bracing and uneven last rows are counted, and occasionally above it when a loader mixes orientations at the door end.

Weight is a second, separate cap: the container’s payload divided by the weight of one carton. The lower of the two caps is what a container can actually take, and each result card shows which one applies.

Pallet mode works on the floor plan instead. It splits the internal width into columns, tries every combination of lengthwise and turned columns, fills each column along the container’s length and keeps the plan with the most floor positions. The loaded height is then checked against the internal height for the tiers you asked for, and the gross weight per pallet, if you entered one, is checked against the payload.