Sizing a padded mailer is a five minute job if you do it in the right order, and an expensive guess if you do not. The order is: pack the product the way it will really ship, measure that, add the flap and clearance allowances, and only then look at a size list.
The method
- Pack a real unit. Bag it, wrap it, add the invoice and the thank you card. A mailer sized to a bare product will not close over a packed one.
- Measure the packed item flat: width at the widest point, length at the longest, and thickness.
- Add about 1/2 in to the width. A padded mailer is not a bag with square corners, and the lining takes up the last part of the width at the edges.
- Add about 1 in to the length so the flap folds over and seals against mailer, not against the product.
- If the item has real thickness, add roughly the thickness again to both width and length, because the mailer has to wrap around the item rather than lie flat over it.
The industry number sizes
Padded and bubble mailers are sold against a numbering convention that is consistent across the trade, quoted as usable internal width by length in inches. Use it as a reference point to sanity check your own measurement, not as a list of stock we hold.
| Number | Usable internal size | What it typically suits |
|---|---|---|
| #000 | 4 x 8 in | Jewellery, cosmetics samples, small electronics parts |
| #00 | 5 x 10 in | Phone cases, small accessories |
| #0 | 6 x 10 in | Paperbacks, small boxed goods |
| #1 | 7.25 x 12 in | Larger books, folded apparel in a bag |
| #2 | 8.5 x 12 in | Letter documents flat at 8.5 x 11 in, small hardbacks |
| #3 | 8.5 x 14.5 in | Legal documents, slim boxed items |
| #4 | 9.5 x 14.5 in | Apparel, A4 documents with clearance |
| #5 | 10.5 x 16 in | Bulkier apparel, multiple items |
| #6 | 12.5 x 19 in | Large soft goods |
| #7 | 14.25 x 20 in | The largest common padded size before a box is the better answer |
When to stop using a mailer
A padded mailer protects against abrasion and light knocks. It does not protect against crush, and it does not hold a shape. If the product is rigid and breakable, if it has corners that can punch through, or if the packed thickness is getting close to the mailer width, a box is the cheaper answer once you count damages. The other stopping point is dimensional weight: carriers bill on size as well as weight, so a thick item in an oversized mailer can cost more to send than the same item in a tight box.
Two more things worth deciding before you order. Whether the mailer needs a second adhesive strip for returns, which is standard on apparel and rare on everything else. And whether you print the inside, which is only worth paying for if the unboxing is part of the product.
Ordering, minimum and lead time
The minimum is 100 units, priced from about $0.48 per unit at bulk volumes and 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 a premium over the nearest number size. 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. Work is made at two plants, West Chicago and Guangzhou.
Measure one fully packed unit, add the flap and clearance allowances, and send the result with your quote request. If you are weighing a mailer against a box for the same product, what size padded mailer do I need works through the decision, and mailer boxes covers the boxed alternative.
