A corrugated mailer is a one piece box with a hinged lid and a front tuck, and it is measured the same way every custom box is measured: inside, in length x width x depth order, where length is the longer edge of the opening and depth is the wall height. Get that order right and most sizing problems disappear.
Inside versus outside, and why it matters twice
You specify the inside because that is what has to hold the product. The outside is what the carrier measures. The difference between them is the board thickness on each side, which is small per wall and meaningful across a parcel. It matters twice over:
- At the packing bench. If a supplier quotes outside dimensions and you assume inside, your product does not fit.
- At the carrier. Dimensional weight is calculated from outside dimensions using the divisor in your own carrier agreement, so a thicker flute can raise the billable weight of an identical shipment.
Flute grade is therefore a sizing decision as much as a strength decision. E flute is thin and prints cleanly, B flute is thicker and tougher, and double wall is thicker again. What flute means in corrugated covers how each one carries load.
Commonly ordered footprints
| Inside size (inches) | Suits |
|---|---|
| 6 x 4 x 2 | Small accessories, jewellery cartons, single cosmetics items |
| 8 x 6 x 2 | Books, small apparel, flat goods with light void fill |
| 9 x 6 x 3 | Mixed small orders, a bottle laid down with padding |
| 10 x 8 x 4 | Multi item orders, mid size electronics with fill |
| 12 x 9 x 4 | Apparel sets, subscription curations, larger multi item packs |
These are the sizes buyers order most, not a fixed range you have to choose from. Because the cutting die is included with your order, a mailer built to the exact interior your product needs costs no more in tooling than one of the rows above.
Sizing method
- Measure the product at its widest, longest and tallest points, as it will actually be packed.
- Add the void fill you genuinely use on each face, not the fill you intend to start using.
- Round up to a practical interior, but only where the extra space earns its place.
- Check the resulting outside dimensions against your carrier's dimensional weight divisor.
- If the billable weight jumps, take the depth back down before you take the protection down.
Ordering
The minimum is 100 boxes per size and artwork. Pricing starts from about $0.48 per unit at bulk volumes, confirmed on a written quote. Included: the die, the printing plates, design support, US shipping and a digital proof before anything prints. Production runs at two plants, West Chicago in the United States and Guangzhou in China. Turnaround is stated per product across Rush (expedited production plus air freight), Standard (air) and Cost saver (sea) lanes, from about 7 business days plus 2 to 5 days for delivery.
Send your product measurements to the quote form for an interior recommendation and a per unit price. See also custom mailer boxes for structure options and die cut mailer dimensions for shaped variants.
