← Resources
One of the first questions a B2B buyer asks when planning a bulk order is: how many tanks will fit in a container? It affects your freight cost per unit, your project budget, and whether splitting a shipment makes economic sense. As a manufacturer, we pack flexible water tanks daily — here is what you actually get.
Why Container Fill Rate Matters
Flexible water tanks ship empty and collapsed, which makes them dramatically more freight-efficient than rigid tanks. A tank that holds 5,000 litres of water may weigh less than 30 kg empty and compress into a bundle roughly the size of a large sleeping bag. That compactness is one of the main reasons buyers choose flexible storage over steel or polyethylene alternatives — and it is worth calculating accurately before requesting a freight quote.
Pillow Tanks: How They Pack
Pillow tanks fold flat, then roll or stack. Smaller units — 900L to 5,000L — are typically folded and rolled into cylinders, then stacked upright or laid on their sides. Larger tanks (12,000L and above) are folded flat and stacked in layers.
Approximate quantities per 20ft container:
- 900L pillow tank — 80 to 100 units
- 4,500L to 5,000L pillow tank — 30 to 45 units
- 8,000L to 12,000L pillow tank — 15 to 25 units
- 18,000L to 28,000L pillow tank — 6 to 12 units
- 48,000L to 60,000L pillow tank — 2 to 5 units
Cube Tanks: How They Pack
Cube tanks collapse flat — the rigid appearance at full capacity disappears entirely when empty. A 4,500L cube tank folds to roughly 10 to 15 cm thick. Cube tanks often achieve higher stack density than pillow tanks of equivalent capacity, especially in mid-range sizes.
Approximate quantities per 20ft container:
- 1,000L cube tank — 60 to 80 units
- 1,500L cube tank — 40 to 60 units
- 4,000L to 4,500L cube tank — 25 to 35 units
- 5,000L cube tank — 20 to 28 units
40ft Containers: When to Use Them
A 40ft standard container offers roughly 2.3 times the volume of a 20ft container and typically costs 30 to 40% more in freight. For large orders of small-to-mid-size tanks, a 40ft container almost always delivers a lower cost per unit. For large tanks (28,000L and above), a 40ft container may only hold 4 to 8 units, at which point the freight economics become similar to a 20ft load.
What Affects the Final Number
Several factors shift the actual quantity above or below these estimates. Fittings pre-attached to the tank reduce packing density compared to fittings shipped separately. A protective ground sheet included per tank adds bulk. Heavier fabric — 1,000 gsm and above — means heavier tanks that may hit container weight limits before volume limits. Non-standard custom shapes may not stack as efficiently as standard product.
Request a Packing List
For any confirmed order, ZolinWorks prepares a detailed packing list showing exact quantities per carton, carton dimensions, gross weight, and container fill rate. If you are comparing freight quotes across suppliers, request this document — it lets you compare on a like-for-like basis.
Send your required tank type, quantity, and destination port and we will confirm the container plan as part of your inquiry response.
Further reading: If container loading is part of a first order, pair this with the China sourcing checklist, then compare the pillow tank range and cube tank range.