20ft Container Plywood Loading: Sheet Count by Thickness (Weight-Limited)
A 20ft container holds either 28 tonnes of plywood or 33 cubic metres of plywood — whichever comes first. For most thicknesses, weight runs out first. 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.
Weight-limited sheet counts by container size
For most packing-grade work — anything from 6 mm up to roughly 18 mm — the 28 t payload caps you before the cube does. The table below assumes 1220 x 2440 mm sheets, the dominant export size.
| Thickness | 20ft GP (28 t) | 40ft GP (26.5 t) | 40HC (26.5 t) |
|---|---|---|---|
| 6 mm | ~2,450 sheets | ~2,320 sheets | ~2,320 sheets |
| 9 mm | ~1,635 sheets | ~1,550 sheets | ~1,550 sheets |
| 12 mm | ~1,225 sheets | ~1,160 sheets | ~1,160 sheets |
| 15 mm | ~980 sheets | ~930 sheets | ~930 sheets |
| 18 mm | ~820 sheets | ~775 sheets | ~775 sheets |
For 1525 x 2440 mm boards, divide the above by 1.25 — the per-sheet weight is 25% higher, so the count drops proportionally.
Volume-limited sheet counts
Past about 20 mm, the geometry flips. The stack runs out of headroom before it runs out of payload, and the 40HC starts to earn its premium. Volume-limited counts for 1220 x 2440:
| Thickness | 20ft GP (33 cbm) | 40ft GP (67 cbm) | 40HC (76 cbm) |
|---|---|---|---|
| 20 mm | ~550 sheets | ~1,115 sheets | ~1,265 sheets |
| 25 mm | ~440 sheets | ~895 sheets | ~1,015 sheets |
These assume tight kraft-paper-lined stacks with no internal pallets eating cube. Add pallets and you lose roughly 8–12% of usable volume.
Three real loading scenarios
Jebel Ali — 18 mm packing-grade, weight-limited
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 ~34 kg per sheet, a 20ft GP fills at roughly 820 sheets and 27.9 t — bang against the payload ceiling, with about 3.5 cbm of empty cube above the stack. No room to upgrade to a 40HC without changing the math, because the 40HC payload is 1.5 t lower than the 20ft. The right answer is two 20ft GPs, not one 40HC.
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, you get ~1,225 sheets and the box hits payload neatly. On four-way entry pallets sized for an MHE-friendly discharge, you lose roughly 100–120 sheets of capacity to the wooden pallet weight and 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 28 mm, a 20ft fills at roughly 390 sheets and only ~20 t — leaving 8 t of unused payload. A 40HC takes the same SKU to ~900 sheets at ~22 t, using the cube but still nowhere near the 26.5 t 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.