Container loading calculator
Work out how many cartons fit in a 20ft or 40ft container, the best orientation, and where to place dunnage bags and desiccants. Free for F&B exporters.
1. Container
2. Product
3. Additional products (optional)
Shipping more than one SKU? Add each product here and the calculator will pack them sequentially from back wall to door.
4. Climate and moisture
5. Orientation
Auto picks the orientation with the highest carton count. Manual lets you lock orientation for label-up rules or arrow marks. Mixed fills the door-end gap with a different orientation.
L is the longest side of the carton, W the next, H the shortest. The label on each edge shows which side of the carton runs along that direction.
Priority: fit as many cartons as possible. Each SKU stacks to its own maximum height.
Add a Requested quantity above to switch strategies.
Enter your carton dimensions and select a container to get started.
Container reference table
Internal dimensions and max payload for the six container types F&B exporters use most. Usable space is what is left after the calculator applies clearances for carton bulge and loading tolerance.
| Container | Internal L × W × H (mm) | Internal CBM | Usable CBM | Max payload (kg) | Reefer load line |
|---|---|---|---|---|---|
| 20ft Standard | 5895 × 2350 × 2392 | 33.1 m³ | 29.2 m³ | 28,200 | — |
| 40ft Standard | 12032 × 2350 × 2392 | 67.6 m³ | 60.2 m³ | 26,680 | — |
| 40ft High Cube | 12032 × 2350 × 2697 | 76.3 m³ | 68.2 m³ | 26,460 | — |
| 20ft Reefer | 5444 × 2290 × 2271 | 28.3 m³ | 23.4 m³ | 27,400 | 2100 mm |
| 40ft Reefer | 11561 × 2290 × 2210 | 58.5 m³ | 50.3 m³ | 27,700 | 2100 mm |
| 40ft HC Reefer | 11561 × 2290 × 2544 | 67.4 m³ | 56.4 m³ | 29,000 | 2350 mm |
Source: ISO 668 with clearances cross-checked against Maersk, ONE, and Hapag-Lloyd container guides. Usable CBM applies 100 mm length, 150 mm width, and 100 mm dry height clearance. Reefer usable height uses the load line minus a 50 mm tolerance for cold-air return.
Built for F&B brand owners and the warehouse teams who load for them.
F&B brand owners need different answers from the people quoting CBM rates. The three questions that come up before every container:
- Will my distributor's reorder fit in one 40ft, or do I need to split it across two 20fts?
- If I push for a high cube, does my reefer cargo still get cold-air return?
- When the warehouse asks for a loading plan at 7am on shipping day, what do I send them?
This tool answers those questions. Built from eight years of loading containers at Popsmalaya, including the shipments where the carton count was wrong and we had to unload the excess at the warehouse, update the packing list, and explain it to the importer.
Real warehouse clearances
100 mm length, 150 mm width, 100 mm dry height. Not a generic 5% buffer. Cartons bulge after a humid container stand. Pallets need approach room. Loading tolerance is real, and the difference between fitting and being short two cartons is usually less than 200 mm.
Sequential block packing for multi-SKU
When a distributor reorders three SKUs at different volumes, the calculator places each SKU in its own best orientation, back wall to door, in the order you list them. The PDF tells the warehouse which block goes where so the slowest-moving SKU lands at the door for first off-load.
Climate-aware desiccant counts
Tropical routes through the equator pull more moisture into the container than mild northern routes. Moisture-sensitive cargo (chocolate, biscuits, dried herbs, single-origin coffee) needs higher desiccant density. The strip count adjusts for both, so you don't over-pay for desiccant on a mild route or under-protect on a tropical one.
How to plan a container load in five minutes
The five steps below mirror the calculator's own workflow. Run them once and the PDF you send the warehouse will already be in their hands by the time they ask.
1. Pick the container type
Choose between 20ft Standard, 40ft Standard, 40ft High Cube, 20ft Reefer, 40ft Reefer, or 40ft HC Reefer. High cube adds about 305 mm of internal height for the same footprint, which is the difference between three and four stack layers on a 600 mm tall carton. Reefer containers have lower usable height because of the T-floor and the load-line ceiling. Pushing cartons above the load line blocks cold-air return and the cargo at the back of the container loses temperature first.
2. Enter carton dimensions, weight, and quantity
Measure the outer carton in millimetres, the gross weight per carton in kilograms, and the quantity you need to ship. For multi-SKU orders, click "Add another product" and enter each SKU separately. The calculator applies the real warehouse clearances automatically and deducts one carton from the back row's top layer for corner-post intrusion so the count matches what physically fits.
3. Pick orientation: auto or manual
Auto-optimise picks the orientation that fits the most cartons. Manual lets you lock orientation when the cartons have arrow marks or when distributors need label faces visible at the door for compliance scans. For multi-SKU loads, every SKU gets its own best orientation independently.
4. Set route climate and moisture sensitivity
Climate and moisture sensitivity drive the desiccant strip count. Tropical routes through the equator (ASEAN to Europe via Suez, ASEAN to North America via the Pacific) need 1.8x more desiccant than mild routes. Sensitive cargo like chocolate-coated biscuits and dried herbs use the higher 0.6 strips per cubic metre rate. Mild routes with standard-sensitivity cargo use 0.2 strips per cubic metre. The calculator multiplies both together so the number on the PDF is what the warehouse should actually load.
5. Download the warehouse PDF
The 3-page A4 PDF is the brief your warehouse team needs before loading day. Page 1 is the loading summary with the 3D view, total cartons, total weight against max payload, and the loading pattern. Page 2 is the door-view cross-section and top-down dunnage placement diagram. Page 3 is the protection checklist with dunnage bag count, desiccant strip count, and door-end restraint instructions. Send it the day before loading and follow up at 7am.
Frequently asked questions
+How many cartons fit in a 40ft container?
It depends on carton dimensions, weight, and stackability. A 40ft Standard container has usable interior dimensions of 11,932 x 2,200 x 2,292 mm after clearance, which is around 60 cubic metres. Enter your carton size into the calculator above to see the exact fit, the best orientation, and any shortfall against your requested quantity.
+What is the difference between dunnage and desiccant?
Dunnage bags are inflatable airbags that fill the void space between cargo and container walls so cartons cannot shift in transit. Desiccants are moisture absorbers that prevent condensation damage to packaging and product. The calculator recommends both based on your cargo volume, carton orientation, route climate, and moisture sensitivity.
+How is the door-end gap calculated?
The door-end gap is the unused length between the last row of cartons and the container door, after subtracting the 50 mm clearance. The calculator shows this gap so the warehouse team can confirm proper restraint at the door end (bracing, straps, load bars, or cargo netting) before closing.
+Can I load multiple products in one container?
Yes. Click 'Add another product' below the primary product form. The calculator uses sequential block packing: each SKU loads in its own optimal orientation, in the order you list it, from back wall toward the door. The PDF lists each SKU with its layout and how many cartons fit.
+What is corner post deduction?
Corner castings at the back of the container protrude inward near the top, blocking one carton slot in the back row's top layer. The calculator applies this deduction automatically when stacking multiple layers so the carton count matches what will actually fit.
+Why does the load line matter for reefer containers?
Reefer containers have a maximum stack height called the load line. Loading above it blocks cold-air return through the T-floor and can damage temperature-sensitive cargo. The calculator uses load-line height instead of internal height for reefer containers, and the door-view diagram shows the line in red.