A padded mailer is sized by the space your product actually occupies inside it, not by the outside of the envelope. The trade numbers the common sizes #000 through #7, and those numbers refer to usable internal dimensions below the seal flap. Below is the numbering as it is used across the industry, followed by the measuring method that matters more than the chart.
The numbered sizes the trade uses
These are industry-typical designations, published and used by many suppliers so that buyers and sellers mean the same thing by "a number 2". Treat them as starting points for conversation. They are not iBox Factory stock sizes, and a custom internal size is quoted the same way.
| Number | Usable internal size (industry convention) | Commonly used for |
|---|---|---|
| #000 | About 4 x 8 in | Jewelry, keys, small electronics accessories |
| #00 | About 5 x 10 in | Phone cases, cosmetics singles |
| #0 | About 6 x 10 in | Paperbacks, small apparel |
| #1 | About 7.25 x 12 in | Hardware, supplement bottles |
| #2 | About 8.5 x 12 in | Documents plus a small item |
| #3 | About 8.5 x 14.5 in | Folded apparel, larger books |
| #4 | About 9.5 x 14.5 in | Two or three folded garments |
| #5 | About 10.5 x 16 in | Bulkier soft goods |
| #6 | About 12.5 x 19 in | Multi-item apparel orders |
| #7 | About 14.25 x 20 in | Large soft goods, bedding singles |
How to measure before you pick a number
- Pack the product the way it will actually ship, folded or bagged, then lay it flat on a table.
- Measure the longest span and the widest span of that flat package. Ignore the label copy, measure the object.
- Add about 1/2 to 1 in to each of those two numbers so the product slides in rather than being pushed in. A mailer that needs forcing tears at the seam.
- Measure the loaded thickness. Padded mailers absorb some thickness, but anything over about an inch usually wants a rigid mailer or a box instead.
- Write the result as internal length x width, and say which measurement is internal on your request.
Internal, external and the seal flap
Two suppliers can quote the same mailer and mean different things. The external size includes the seal flap and the sealed side seams, which is why an envelope printed 6 x 10 in may measure closer to 6 x 11.5 in on the outside. When you compare quotes, compare usable internal dimensions with the flap excluded. If a spec sheet does not say, ask. This one detail is the most common cause of a mailer arriving a half inch short of the product.
Padded, bubble lined or corrugated
Padded kraft and bubble lined mailers cushion soft and semi-rigid goods. Anything with a corner that can be crushed, a screen, or glass usually does better in a die cut corrugated mailer box, where the board itself carries the load. If your product falls between the two, send both options to the quote and let the packing test decide. For box style comparisons, see mailer box dimensions, or order printed mailer boxes directly.
Ordering, print and turnaround
Custom printed mailers run from a 100 unit minimum, from about $0.48 per unit at bulk volumes, confirmed on your written quote. The die, the plates, design support, US shipping and a digital proof before anything prints are included. Production runs out of West Chicago in the US or Guangzhou in China depending on the finish and the lane you choose. Turnaround is quoted per product in three lanes: rush (expedited production plus air freight), standard (air) and cost saver (sea), with a floor of about 7 business days in production plus 2 to 5 days for delivery. Rush adds a premium of about 7 to 25% depending on the job.
If you already know your flat product size, send it with the quantity and we will come back with the internal dimension, the board options and a price. Request a quote and include the two flat measurements you took above.
