20ft Container Plywood Loading: Sheet Count by Thickness
A 20ft container holds either 28 tonnes of plywood or 33 cubic metres of plywood — whichever comes first. For a 20 ft the space runs out first; only in a 40 ft high-cube does the weight. Here's the math, worked through for the sheet sizes and grades we ship out of Cochin every week.
The number that matters to your CHA, your freight forwarder, and your customer is not the brochure capacity of the container — it is the actual sheet count that fits under the road-legal payload ceiling at the load port. Get this wrong and you either pay for empty space or get turned away at the gate.
Container capacity primer
Three boxes do almost all the plywood work moving out of Cochin Port:
| Container | Internal volume | Max payload (typical) | Internal floor (L x W) |
|---|---|---|---|
| 20ft standard (GP) | ~33 cbm | 28,000 kg | 5.90 m x 2.35 m |
| 40ft standard (GP) | ~67 cbm | 26,500 kg | 12.03 m x 2.35 m |
| 40ft high-cube (HC) | ~76 cbm | 26,500 kg | 12.03 m x 2.35 m |
The 20ft GP is the workhorse for dense cargo like plywood — its payload (28 t) is actually higher than the 40ft (26.5 t) because the tare weight of a longer steel box eats into the gross limit. The 40HC buys you 9 extra cubic metres at the same payload, which only helps if your stack is volume-limited (thick boards or low-density faces).
Country-specific axle rules will tighten these numbers further. EU and UK destinations frequently cap inbound 20ft boxes at 24–26 t over the road; Middle East and West African ports are usually fine at the full 28 t. Always confirm with the destination forwarder before quoting a sheet count.
Plywood weight per sheet
Hardwood-faced packing-grade and BWR plywood at the densities CWI typically ships (roughly 620–680 kg/cbm depending on core species and glue) gives these per-sheet weights. The two standard export sizes are 1220 x 2440 mm (4 x 8 ft) and 1525 x 2440 mm (5 x 8 ft).
| Thickness | 1220 x 2440 — kg/sheet | 1525 x 2440 — kg/sheet |
|---|---|---|
| 4 mm | ~7.6 | ~9.5 |
| 6 mm | ~11.4 | ~14.3 |
| 8 mm | ~15.2 | ~19.0 |
| 9 mm | ~17.1 | ~21.4 |
| 12 mm | ~22.8 | ~28.5 |
| 15 mm | ~28.5 | ~35.6 |
| 18 mm | ~34.2 | ~42.8 |
| 20 mm | ~38.0 | ~47.5 |
| 25 mm | ~47.5 | ~59.4 |
Treat these as planning numbers. Actual weights on the bill of lading will vary by ±3% with moisture content and the specific core species — gurjan and birch run heavier, eucalyptus and rubberwood run lighter.
Sheet counts by container size
These come from the same loading engine that produces our quotations, at an assumed panel density of 650 kg/m³ on 8 ft × 4 ft sheets, and with the clearances the yard actually works to: 100 mm at the roof, 50 mm each side, 100 mm at the doors and 50 mm between bays.
The result is the opposite of the rule of thumb most people quote. A 20 ft box runs out of space long before it reaches its plate payload: at every thickness below it closes at roughly 16 tonnes against 28,230 kg allowed. The 40 ft high-cube is the box that runs out of weight, closing at about 26.3 tonnes. If you are weight-limited you are almost certainly in a 40 HC, not a 20 ft.
| Thickness | 20 ft loose | 20 ft palletised | 40 HC loose | 40 HC palletised |
|---|---|---|---|---|
| 4 mm | 2,096 | 1,824 | 3,399 | 3,244 |
| 6 mm | 1,400 | 1,216 | 2,266 | 2,163 |
| 9 mm | 932 | 808 | 1,511 | 1,442 |
| 12 mm | 700 | 608 | 1,133 | 1,081 |
| 15 mm | 556 | 480 | 906 | 865 |
| 18 mm | 464 | 404 | 755 | 721 |
| 19 mm | 440 | 380 | 715 | 683 |
| 25 mm | 332 | 288 | 543 | 519 |
Loose counts assume tight stacks with no pallets. The palletised counts already include the pallet, side boards and straps at 50 kg per pile, which costs roughly 10–13% of the sheet count.
Treat these as ceilings, not promises. The figure on your loading plan is worked out from the measured density of your actual lot, the bundle geometry, the container’s CSC plate, the VGM and the road weight limit at the destination — several of which are lower than the plate.
Three real loading scenarios
Jebel Ali — 18 mm packing-grade
A common Middle East profile: 18 mm 1220 x 2440 packing-grade ply, bound for industrial-equipment crate makers in the Jebel Ali Free Zone. At about 34 kg a sheet, a 20 ft GP fills at roughly 464 sheets loose and only 16.1 t. It runs out of room, not payload, and leaves about 12 t of the plate unused. The same panel in a 40 HC reaches 755 sheets at about 26.3 t, where weight finally closes the box. For 18 mm the 40 HC is the efficient answer: 63% more material in one box, and the only one of the two that is actually weight-limited.
Singapore — 12 mm BWR, mixed pallets vs loose sheets
12 mm BWR plywood headed for furniture and joinery distributors in Singapore is the textbook "do we pallet or not" call. Loose-loaded into a 20ft GP the engine gives 700 sheets at about 16.2 t — the box runs out of room with roughly 12 t of its payload unused, which is the opposite of what most people expect. On four-way entry pallets sized for an MHE-friendly discharge you drop to 608, losing capacity to the pallet itself and to the gaps between stacks — call it ~1,100 sheets per 20ft. Customers who run their own forklifts at the destination yard usually take the loose load and accept the longer discharge time. Customers discharging at a 3PL warehouse pay for the pallets every time.
Hamburg — 28 mm container flooring, cube vs weight tradeoff
28 mm hardwood-core flooring panels for the container repair and reefer trade in northern Europe are the volume-limited end of the spectrum. At 65–75 kg per 2440 × 1220 × 28 mm sheet, a 20ft is payload-limited at roughly 373–396 sheets before packing allowance. A 40ft HC takes roughly 353–407 sheets on the same limit, so the cube is never the binding cap. For this profile we always quote the 40HC; the per-sheet ocean freight drops by close to 40%.
Lashing, kraft sheet and desiccant
Standard CWI export loads include the following, built into the FOB Cochin price:
- Kraft paper top sheet and corner protection on every stack
- Polyester strap banding around each bundle
- Front-wall and door-side wooden dunnage to prevent stack shift
- Two desiccant bags per 20ft (four per 40ft) for monsoon-season sailings
Extra-cost options on request:
- Heat-treated ISPM-15 pallets (when the destination requires palletised discharge)
- Shrink-wrap over the entire bundle for high-humidity ports
- Container liner bags for ocean routes with known condensation issues
- Tally certificate and pre-shipment inspection coordination
Group operations in Perumbavoor since 1986 have given us about forty years of loading boxes out of Cochin Port — long enough to know that the right loading plan is the one your customer signs off on before the container leaves the factory yard, not after.
Quote with the loading plan, not just the rate
Send us your destination port, thickness, sheet size and target quantity. We will come back with a quote that names the container type, the sheet count it actually fits, and the payload weight on the bill of lading — so your CHA and your buyer see the same numbers we do. Start a quote here.