Container Load Calculator. Fill the box, not the bill.

A 20ft standard container measures roughly 5.9 × 2.35 × 2.39 metres inside, about 33 m³. A 40ft standard is twice the length at roughly 12 metres, about 68 m³. The catch is weight: a 40ft can carry around 26,700 kg of cargo, slightly less than a 20ft's 28,200 kg. So dense, heavy goods often hit the payload limit in a 20ft long before they fill a 40ft, while light, bulky goods suit the bigger box.

A high cube is about 300 mm taller than a standard container (roughly 2.7 metres internal height instead of 2.39) on the same footprint. A 40ft high cube gives you around 76 m³ instead of 68 m³. It is the go-to for light, bulky goods like apparel, homeware or packaging, and it can sometimes make room to double stack pallets that would not fit two high in a standard box.

Laid out in a single orientation, the calculator fits 8 UK standard (1200 × 1000 mm) or 8 Euro (1200 × 800 mm) pallets in a 20ft, and 20 of either in a 40ft, in a single tier. Loading by hand with some pallets turned can squeeze in a few more, especially Euro pallets, so treat the figure as a safe planning number and confirm the final count with your forwarder.

Each container has a maximum payload, the cargo weight it is rated for on top of its own tare weight. Typical figures are around 28,200 kg for a 20ft and 26,700 kg for a 40ft standard. In practice, road weight limits in the country of collection or delivery often cap the load well below that, so check with your haulier before you plan to the container's full rating.

Floor loading cartons straight into the container uses the space better, often fitting noticeably more stock, and avoids the cost of pallets. The trade off is unloading: loose cartons are handled one by one, and many 3PLs charge a devanning fee per container for floor loaded freight. Palletised loads unload in minutes and go straight into racking. Run both modes in the calculator to see the difference for your cartons, then weigh it against your warehouse's handling charges.

A reefer is a refrigerated container for chilled or frozen goods such as food, beverages and some cosmetics. The insulation and refrigeration unit take up space and add weight, so a 20ft reefer is smaller inside (about 28 m³) and heavier empty than a 20ft dry container. Plan reefer loads with the reefer presets rather than the dry ones, and leave room for air to circulate around the cargo.

Only if the height allows and the goods can take it. Two loaded pallets have to fit under the container's internal height, and the bottom load has to bear the full weight of the one on top, which is usually the real limit rather than the container itself. Sturdy, uniform cartons stack well; fragile goods, liquids and irregular loads generally should not be double stacked. Tick double stack in the calculator and it will tell you whether two tiers fit.