The short answer: the right padded mailer is the smallest one your packed item fits into with about half an inch of width clearance and about an inch of length spare for the flap. Everything else is checking that answer against how the item actually ships.
Work it out in four steps
- Pack one unit completely, including the poly bag, the packing slip and the thank you card.
- Lay it flat and measure width, length and thickness.
- Add about 1/2 in to width and about 1 in to length. If the item has noticeable thickness, add roughly that thickness again to both, because the mailer has to wrap rather than lie flat.
- Round up to the next available size and check the fit with a real sample before committing to a run.
Questions that decide it
Does the stated mailer size include the flap?
Normally not. Padded mailer sizes are quoted as the usable internal area, and the sealing flap sits above that. If a supplier quotes an outside measurement instead, the usable space will be smaller than the number suggests, so ask which one you are being given.
My product is rigid. Is a mailer still right?
Padded mailers protect against scuffs and light knocks, not against crush or a corner impact. A rigid, breakable item is better off in a box, and a rigid item with sharp corners will eventually punch through a lining. If the packed thickness is getting close to the mailer width, that is the point to switch.
Will a bigger mailer cost me more to ship?
It can. Carriers bill on dimensional weight as well as actual weight, so a thick, loosely filled mailer can be rated above a tight one holding the same product. Oversizing also lets the item move, and movement is what causes the damage a padded mailer was bought to prevent.
One size or several?
Most sellers end up with two or three. One size for the small, flat majority of orders, one for the bulky outlier, and sometimes a middle size if the order mix justifies the extra SKU on the packing bench. Work out the split from your actual order history rather than from the catalogue range.
Mistakes worth avoiding
- Measuring the product rather than the packed unit.
- Forgetting the lining. A padded mailer has less usable width than its outside dimension implies.
- Choosing a size from a photo of a competitor product instead of from your own item.
- Buying one large size to cover everything, then paying dimensional weight on every small order.
- Skipping the sample check on a first run, then discovering the flap lands on the product instead of on the mailer.
Ordering
Custom printed mailers start at 100 units, 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 printing are included, so a size cut to your own product is not more expensive than the nearest standard. Production is quoted per product in three lanes, rush (expedited production plus air freight), standard (air) and cost saver (sea), from about 7 business days, plus 2 to 5 for delivery. We make at two plants, West Chicago and Guangzhou.
Measure one packed unit and send the three numbers with your quote request and we will confirm the size against the sizes available in your lane. The full measuring routine, with the industry standard number sizes for reference, is on how to size a padded mailer.
