How To Calculate Container Loading Quantity For Bathtub And Shower Base
Freight is often the difference between a profitable import order and a marginal one — yet many buyers accept a factory's "X pcs per container" figure without checking the math. Bathtubs and shower bases are bulky, low-density cargo, which means most containers fill up by volume before weight. This guide shows you how to calculate container loading bathtub quantities yourself, work through real examples for 20GP and 40HQ containers, and apply practical freight cost optimization tactics before your next order.
Step 1: Know Your Container Dimensions
Start with the internal dimensions of standard containers:
| Container | Internal L × W × H | Typical Door Opening |
|---|---|---|
| 20GP | ~5.90 × 2.35 × 2.39 m | 2.34 × 2.28 m |
| 40GP | ~12.03 × 2.35 × 2.39 m | 2.34 × 2.28 m |
| 40HQ | ~12.03 × 2.35 × 2.69 m | 2.34 × 2.58 m |
Payload limits (roughly 28,000 kg for 20GP, 26,000 kg for 40HQ under road rules in most destinations) rarely constrain bathroom ware, since a pallet of acrylic tubs weighs far less per cubic meter than dense cargo. Always confirm final loading numbers with your forwarder, as actual internal dimensions vary slightly by container build.
Step 2: Get The Packed Carton Size From Your Supplier
The single most important data point is the packed carton dimension, not the product size. A 1700 × 800 × 580 mm freestanding tub packs into a carton of roughly 1720 × 820 × 620 mm depending on protection method. Ask every supplier for:
- Packed carton L × W × H per model (in mm)
- Gross weight per carton
- Packing method: carton only, carton + foam frame, or palletized
- Whether tubs can nest (two or three tubs per carton) — this changes everything
For a freestanding acrylic bathtub with rim-drain fittings packed separately, nesting is usually possible with foam interlayers. For skirt bathtubs, cartons are flatter and stacking-friendly.
Step 3: Worked Example — 20GP Loading A 1700 mm Freestanding Tub
Assume: carton 1.72 × 0.82 × 0.62 m, gross weight ~45 kg per carton, tubs nested two per carton where agreed.
- Carton volume: 1.72 × 0.82 × 0.62 ≈ 0.874 m³
- Usable 20GP volume: 5.90 × 2.35 × 2.39 ≈ 33.2 m³; with loading losses (door area, uneven stacking) plan on ~28–30 m³ effective
- Cartons fit across width: 2.35 / 0.82 ≈ 2 rows (0.82 m each side) + remaining strip
- Cartons along length: 5.90 / 1.72 ≈ 3 per row per layer
- Layers: 2.39 / 0.62 ≈ 3 layers
Realistic result: approximately 20–24 cartons, i.e. 40–48 tubs with 2-per-carton nesting. Your supplier's quoted number should fall in this band — if someone quotes 60 tubs in a 20GP for this model, check whether the carton spec is thinner protection or whether they are overestimating.
Step 4: Worked Example — 40HQ Mixed Loading With Shower Bases
Mixed-container loading is where real freight cost optimization happens. A 40HQ offers ~76 m³ gross; plan on ~65–70 m³ effective.
Example plan:
| Item | Carton Size (m) | Cartons | Volume Used |
|---|---|---|---|
| Freestanding tub 1700 (2/case) | 1.72 × 0.82 × 0.62 | 40 | ~21.7 m³ |
| Built-in tub 1500–1800 | 1.55 × 0.78 × 0.45 | 60 | ~32.6 m³ |
| ABS shower base 900 × 900 | 0.95 × 0.95 × 0.25 | 45 | ~10.2 m³ |
Total ≈ 64.5 m³ — a full 40HQ with a balanced product mix. Note that shower bases, being flat and stackable, are excellent "gap fillers" placed on top of tub cartons in the last loading phase. Confirm stacking strength: tub cartons with foam frames can usually carry one layer of base cartons; the factory's packing team should confirm.
Step 5: Palletized vs Loose Loading
This is a decision with real cost consequences:
- Palletized packing: faster loading/unloading, less handling damage, easier warehouse moves — but pallets consume 10–15% of container volume, so fewer units fit.
- Loose (hand-stacked) loading: maximum quantity per container, common for China-to-US/EU FOB shipments where the receiver controls unloading.
A middle path many importers use: palletize the small, fragile items (shower bases, fitting boxes) and hand-stack the tub cartons. Whichever you choose, state it in the purchase order, because it changes the packing cost and the loadable quantity. Factories that optimize pallet plans and 20GP/40HQ loading layouts — as part of standard export service, like YUNCCI's export support — will provide a packing plan with photos before the container is sealed.
Step 6: Quick Checklist Before Confirming Any Loading Plan
- Written packing plan showing carton counts and placement diagram
- Carton drop-test or at least corner protection confirmation for ocean freight
- Photos of the loading process and container seal number
- Weight distribution across the container floor (heavy cartons at bottom, spread evenly)
- Container type confirmed with your forwarder: 20GP, 40GP, or 40HQ
Summary
- Bathroom ware is volume-limited, not weight-limited: calculate with packed carton dimensions, not product dimensions.
- A 1700 mm freestanding tub typically loads 40–48 pcs (nested) in a 20GP; verify any quote against carton math.
- Mixed 40HQ loading with flat shower bases as top-layer fillers improves utilization significantly.
- Palletizing costs 10–15% of volume; decide based on your destination handling and state it in the PO.
- Always require a written packing plan and loading photos before the container is sealed.
Ready to source? Contact us for FOB quotation and product catalog. YUNCCI provides palletized packing, 20GP/40GP/40HQ loading optimization, and a written packing plan with every shipment. Email [email protected] or WhatsApp +86 195 6415 0915. See packing-ready product lines including the freestanding acrylic bathtub and ABS shower base at https://www.yuncci.com.