Container Loading Calculator

Carton dimensions rarely divide evenly into a container's inner dimensions, so some unusable space is always left along the edges. For a single carton size, this tool packs right up to the theoretical maximum for edge-to-edge (guillotine) cutting — for example a 60×40×40 cm carton: 260 in a 20GP, 550 in a 40GP, 660 in a 40HC.

Door openings are shorter than the container's inner height by about 11–12 cm: a standard container's door is about 227 cm, a high-cube's about 257 cm. Cargo whose height falls between the door opening and the inner height fits inside but can't be carried through the door — this tool flags that separately and suggests a high-cube or laying the carton on its side instead.

Common inner dimensions: 20GP 589×235×239 cm, 40GP 1,203×235×239 cm, 40HC is 269 cm tall, 45HC is 1,355 cm long. Door openings use the smaller of the published figures from two major carriers. Actual dimensions vary slightly by carrier — leave some margin when a plan is close to full. Default weight limits (20GP 21,700 kg, 40GP/40HC 26,500 kg, 45HC 27,500 kg) are common values — the number on your box's PAYLOAD plate on the door is the one that counts, and trucking or port limits can be lower; change it in settings if so.

Steel parts, hardware and similar dense cargo often hit the weight limit before running out of space. This tool checks volume, weight and center of gravity together: when a container isn't full, it tries to shift the load toward the middle along the length and width, and the open ends or sides left over need dunnage or airbags packed in on site. When the center of gravity is still noticeably off, sits high, or a single small-footprint item is carrying a concentrated load, the result explains what to do about it (spread the weight out, add lengthwise dunnage or a beam, switch to an open-top or flat-rack container, and so on). Weight limits vary by port and trucking company — you can change the max load in settings (that figure is cargo only, excluding the container's own tare weight). These center-of-gravity and concentrated-load thresholds follow the suggested values in the international CTU packing guidelines, for reference only — they don't replace written confirmation from your forwarder or carrier.

Lie on its side: pick "can lie on its side" for plain cartons with no "this side up" requirement — it often lets you fit more. Keep "upright only" for anything direction-sensitive. Max stack layers: this counts the carton itself, so entering 1 means nothing can be stacked on top of it. If the carton is marked per ISO 780 with a stacking limit of n (meaning n more may be stacked above it), enter n+1; if it's marked with a total layer count instead, enter that number directly; when unsure, enter the smaller, more conservative value. Max load on top: check the stacking-limit mark on the carton or ask the factory for the compression rating, then enter it — the tool converts that into a maximum stack height for you. All of these are under "more" on each line.

Use this when one container unloads at more than one destination. Enter a port for each line: cargo for the first stop is loaded nearest the door, cargo for the last stop goes in deepest — so nothing has to be moved out of the way at the first stop.

Under "more" on a line, choose "palletize first" (or check "palletize everything" in settings to apply it to the whole shipment), pick a pallet size, max height and max weight per pallet. The tool works out how many cartons fit per pallet and how many pallets you need, then loads each full pallet as if it were a single piece of cargo.

No. The file is read entirely in your browser; only the dimensions, quantities and weight it extracts go into the cargo table. If it picks the wrong column, unit, or reads a subtotal row as a single carton's weight, you can fix it in the import preview before it's added — and rows missing carton dimensions can be filled in right there. Older .xls files should be saved as .xlsx first.

The same way loaders do it by hand: building wall by wall from the back of the container toward the door, filling the floor of each wall before stacking upward, keeping the same cargo together where possible. Heavier cargo goes on the bottom: nothing is stacked on a piece that weighs less than itself; cargo marked "do not stack" never has anything placed on it. A free-standing stack that isn't braced against other cargo or the container wall is kept to no more than 3× the height of its shorter base edge; a stack over 1.25× still needs to be lashed in transit even though it's allowed to stand (the result flags it). "Play loading sequence" and the loading diagram show this same order: back to front, bottom to top.

This is the count for cartons packed to exact, regular dimensions. Real cartons bulge slightly, dimensions have tolerances, and forklift work leaves some gaps — so actual loads often run a few cartons short of the calculated number. When quoting, it's safer to say "about N cartons." Any gaps in the plan, the door face, and individual heavy items still need on-site blocking and lashing; irregular cargo should be confirmed on-site.