Sizing a single wall box is a four step job and none of the steps involve picking from a chart. Single wall describes the board, one fluted medium glued between two liners, and it tells you nothing about the size. The size comes from your product.
Step 1: measure at the widest, not the nominal
Products are rarely the size they are described as. Measure each axis at its actual widest point, including handles, lids, caps, labels and any bagging the product wears into the box. If you are boxing several items, arrange them exactly as they will be packed and measure the arrangement as one block.
Step 2: add clearance for whatever is between product and board
Clearance is not a fudge factor, it is the space your protection occupies. A corrugated pad adds its own caliper on each side it covers. Void fill needs room to compress. An insert has a wall thickness. Add the real thickness of the real protection, and if the product must not move at all, size the insert and then size the box around the insert.
Step 3: state it as internal length x width x depth
Corrugated is written L x W x D, where length and width are the two dimensions of the opening and depth is measured from the closed bottom to the closed top. Length is conventionally the longer opening dimension. Say explicitly that the numbers are internal, because a quote read as external will come back a full board thickness small on every axis.
Step 4: check the flute against your external limit
If the box has to fit something, a shelf, a master carton, a locker or a carrier limit, you need the external number too. As a first approximation, each dimension grows by about twice the board caliper, plus manufacturing tolerance.
| Flute | Approximate caliper | Typically used for |
|---|---|---|
| A | About 3/16 in | Cushioning and stacking strength where the box has room to be thick |
| C | About 5/32 in | The general purpose shipping flute |
| B | About 1/8 in | Flatter panels, better printing, good puncture resistance |
| E | About 1/16 in | Retail cartons and mailers where print quality matters |
| F | About 1/32 in | Small retail packs replacing heavy paperboard |
These are published industry calipers offered as a starting point, not a list of iBox stock sizes. The exact caliper varies by mill and by grade, so confirm the board on your quote.
When single wall stops being the answer
Single wall covers a wide band of everyday shipping. It stops being right when the packed weight is high, when boxes stack several high in a warehouse for weeks, or when the lane is rough. That is a board conversation rather than a size conversation, and ECT in corrugated board explains the vocabulary you will hear.
Ordering and what it costs to be exact
Minimum order is 100 boxes, from about $0.48 per unit at bulk volumes, confirmed on your written quote. The die and plates, design support, US shipping and a digital proof before anything prints are included, which is the reason there is no advantage in rounding your size to something that looks standard. Turnaround is quoted in three lanes: Rush (expedited production plus air freight), Standard (air) and Cost saver (sea), with a floor of from about 7 business days, plus 2 to 5 for delivery, and specialty imported items up to about 12 weeks. Rush adds about 7 to 25%, depending on the job.
Give us the product measurements and the protection you intend to use and we will come back with an internal size, a board grade and a price at /quote/. If you would rather work from an existing style, corrugated boxes is the place to order.
