Double wall is the board you choose when single wall is not holding up: heavy contents, long transit, or a pallet that has to stack. Sizing it uses the same method as any corrugated box, with one important difference. Double wall board is thick, so the gap between the internal size you need and the external size you ship is much wider than people expect.
Step 1: measure the product at its widest
Not at the label, not at the nominal size. Handles, feet, moulded ribs and protruding caps decide the number. Take three figures, length, width and height, and write down which orientation the product sits in inside the box, because that determines which product axis maps to box depth.
Step 2: add clearance for the protection you will actually use
Clearance is not a fudge factor, it is the space your cushioning occupies. Decide the protection first:
- Corrugated partitions or pads: add the pad thickness on each side that gets one.
- Loose fill or paper void fill: add enough on every axis for a continuous layer, not a token gap.
- Foam or moulded pulp: add the tray wall thickness, which is usually thicker than it looks on a render.
Step 3: add the board itself
Here is where double wall differs. Each wall consumes the full board caliper, so every axis loses roughly twice the caliper between inside and outside. Industry-typical single-flute calipers give you a workable estimate:
| Flute | Industry-typical caliper | Common role |
|---|---|---|
| E | about 1.6 mm | Retail cartons, printed mailers |
| B | about 3.2 mm | General purpose single wall |
| C | about 4.0 mm | Shipping boxes, better stacking |
| BC double wall | about 7 mm | Heavy or long transit loads |
| EB double wall | about 4.8 mm | Print quality outside, extra strength inside |
These are published industry-typical board figures used as a starting point, not iBox stock specifications. The exact caliper on your job is confirmed on the quote.
Step 4: write it down in the right order and say internal
State internal length x width x depth. Length is the longer opening edge, width the shorter, depth the height from the inside floor to the top of the walls. Then write the word internal next to it. This single habit prevents the most common re-tooling conversation in corrugated packaging.
Step 5: sanity check against the pallet
A standard US pallet is 48 x 40 inches. Before you fix the external size, check how many of your boxes tile onto that footprint without overhang. An external dimension a few millimetres smaller can add a whole extra box per layer, and that saving repeats on every pallet you ever ship.
Ordering
Minimum order is 100 boxes, and pricing starts from about $0.48 per unit at bulk volumes, confirmed on your written quote. Die and plates, design support, US shipping and a digital proof before anything prints are included. Turnaround is stated per product in three lanes: rush combines expedited production with air freight, standard goes by air, and cost saver goes by sea, from about 7 business days, plus 2 to 5 for delivery. Specialty imported items can run up to about 12 weeks. The boxes are made in West Chicago and in Guangzhou.
If you are still deciding whether double wall is the right call at all, what size double wall box do I need works through it from the symptoms. To order the structure, see double wall tuck top boxes. Send your measured product, your chosen protection and your pallet target to request a quote.
