Start with usable CBM, not the container name
A 20ft general purpose container measures about 5.9 m long, 2.35 m wide and 2.39 m high inside, which works out to roughly 33.2 CBM. A 40ft GP is about 67.7 CBM. A 40ft high cube adds 30 cm of height and reaches roughly 76.4 CBM. Those are the published interior figures.
They are not the figures you can fill. Cartons do not tessellate into a steel box, the door opening is smaller than the interior, and the last row needs bracing. Plan on 85–90% of internal volume: about 28–29 CBM in a 20ft and 65–68 CBM in a 40HQ. On a 20ft the gap is five cubic metres, roughly 70 cartons of block sets, so put the loss into your cost sheet before you negotiate FOB.
CBM is length × width × height in metres. A carton of 50 × 36 × 38 cm is 0.5 × 0.36 × 0.38 = 0.0684 CBM. Divide usable volume by carton CBM to get cartons per container, then multiply by pieces per carton.
Weight limits rarely bind on wooden toys
A 20ft container is rated for about 28,000 kg of payload and a 40HQ for about 26,500 kg, but those ISO ratings are not what you can legally move. In the US, a 20ft box on a chassis under a standard tractor reaches the 80,000 lb (36,300 kg) gross vehicle limit long before the container is full; practical cargo lands nearer 20–22 tonnes. European road limits produce similar results.
Packed wooden toys typically run 150–300 kg per CBM. A 40HQ loaded to 66 CBM at 250 kg/CBM carries about 16.5 tonnes, roughly 60% of the payload rating. You hit the volume ceiling with the container still ten tonnes under its weight limit. That single fact drives most packaging decisions in this category: the cheapest container is the one where you remove air, not grams.
The exception is dense product. Solid hardwood blocks, thick ply puzzles and book sets can approach 400 kg/CBM, and a 20ft may go overweight before it goes full. Ask for gross weight per carton and run the sum per SKU, not per order.
Load factor: where the last 10% goes
Four things eat volume: pallets, mixed carton sizes, stack height and bracing.
- Pallets. A 1200 × 1000 mm pallet fits two-wide in a 20ft with little waste, but the pallet itself is 15 cm of dead height and 20–25 kg. Floor loading gains 8–12% volume on a 20ft, more on a 40HQ.
- Mixed SKUs. One carton size stacks cleanly. Five SKUs with five heights leave gaps at the top of each block, and mixed orders lose 5–8% against the pure-SKU maximum.
- Stack height. Cartons crush. A 5-ply export carton of wooden toys usually takes 6–8 high, and the bottom layer carries the load. Tell the supplier the container and let them specify ply and compression strength.
- Bracing. Airbags and timber dunnage take space and money, but a shifted load is a rejected claim.
Carton sizes and pieces per container
Indicative figures for typical catalogue items, calculated at 28.4 CBM usable in a 20ft GP and 66.5 CBM in a 40HQ, full cartons only, no pallets. Treat them as planning numbers and confirm against the carton spec on your quote.
| Item | Carton (cm) | CBM / carton | Pcs / carton | Pcs per 20ft | Pcs per 40HQ |
|---|---|---|---|---|---|
| 100-pc block set | 50 × 36 × 38 | 0.068 | 6 | 2,490 | 5,830 |
| 9-pc chunky puzzle | 44 × 34 × 36 | 0.054 | 12 | 6,320 | 14,810 |
| Tabletop bead maze | 40 × 40 × 30 | 0.048 | 4 | 2,360 | 5,540 |
| Shape sorter | 48 × 36 × 40 | 0.069 | 8 | 3,280 | 7,700 |
| 40-pc train set | 46 × 34 × 28 | 0.044 | 6 | 3,890 | 9,110 |
| Flat-pack play kitchen | 62 × 42 × 12 | 0.031 | 2 | 1,820 | 4,260 |
Two readings matter. Piece counts are large for small items and small for furniture-scale items: a play kitchen is 2 pcs per carton and about 4,260 pcs in a 40HQ, which is more than most importers want in one go. And the flat-pack kitchen carton is only 0.031 CBM, so its freight per unit is roughly a third of the block set's, because there is almost no air inside it.
Four ways to cut freight per unit
Freight per unit is carton CBM ÷ pieces per carton × freight rate per CBM. You can attack all three. The rate is mostly market; the other two are design decisions.
- Flatten and knock down. A play kitchen shipped assembled is mostly air. Flat-packed with cam locks and a proper dieline, the same kitchen drops from about 0.11 CBM to 0.03 CBM per unit.
- Nest. Stacking chairs, sorting bins and bucket-style toys nest. A 12 mm nesting gap across five components can cut carton height by a third.
- Right-size the carton. Suppliers default to the master case that suited the last customer. Ask for 10 mm off each dimension and re-run the drop test; the saving is real only if the carton still passes ISTA 1A or 3A.
- Load the container you actually fill. Two half-full 20fts cost more than one 40HQ. If your order is 30 CBM, ask for a 40HQ quote and a mixed-pallet plan. The per-unit difference often lands at 10–20%, and freight rates move, so treat that as indicative.
Do not trade protection for volume. A thinner carton that fails in transit is a chargeback, not a saving.
What to ask the supplier before you book
- Carton dimensions in cm, CBM per carton, pieces per carton and gross weight.
- Carton grade, burst or compression test result, and maximum stack height.
- Pallet pattern (1200 × 1000 or 1200 × 800), cartons per pallet, pallet height, and ISPM 15 heat treatment.
- Whether they can mix SKUs in one container, and the minimum per SKU.
- HS code 9503.00 and the FOB port. Ningbo and Shanghai differ on rates and sailing schedules.
- A loading plan or a set of loading photos before the doors close.
A supplier who can send a carton spec sheet and a loading plan on day one has usually shipped this product before. Ask for both with your request a quote and compare landed cost per unit, not FOB price.
Next step
Send your SKU list with target quantities and we will return carton dimensions, CBM per unit and a container plan for 20ft, 40ft and 40HQ. Start with request a quote, or browse the catalogue for the ranges that fit your shelf.
