The Fold · From the factory floor
What are the standard poly mailer sizes?
The standard poly mailer sizes run from 6 × 9 inches up to 19 × 24 inches, and 10 × 13 inches is the one most people end up ordering. The size you see is the outside width and height with the flap not counted, so what you can actually fit inside is a little smaller.
All 13 standard sizes
Poly mailers don't come with one official size chart, but these thirteen are the sizes that keep coming up. Each is width × height on the outside, in inches, with millimetres for anyone drawing a dieline.
| Size | Outside | Usable inside |
|---|---|---|
| 6 × 9 in | 152 × 229 mm | 5.2 × 8.3 in |
| 7 × 10 in | 178 × 254 mm | 6.2 × 9.3 in |
| 7.5 × 10.5 in | 190 × 267 mm | 6.7 × 9.8 in |
| 9.5 × 12 in | 241 × 305 mm | 8.7 × 11.3 in |
| 10 × 13 in (most popular) | 254 × 330 mm | 9.2 × 12.3 in |
| 12 × 14.25 in | 305 × 362 mm | 11.2 × 13.5 in |
| 12 × 15.5 in | 305 × 394 mm | 11.2 × 14.8 in |
| 13.5 × 19 in | 343 × 483 mm | 12.7 × 18.3 in |
| 14 × 18 in | 356 × 457 mm | 13.2 × 17.3 in |
| 14.5 × 19 in | 368 × 483 mm | 13.7 × 18.3 in |
| 15 × 18 in | 381 × 457 mm | 14.2 × 17.3 in |
| 19 × 23 in | 483 × 584 mm | 18.2 × 22.3 in |
| 19 × 24 in | 483 × 610 mm | 18.2 × 23.3 in |
That last column is the one most size charts leave out. A poly mailer loses about 0.8 in of width and 0.7 in of height to its side seams and sealing strip, so a 10 × 13 mailer really holds something that is 9.2 × 12.3 in or smaller.
Which size fits what
These are starting points, not promises.
- 6 × 9 to 7.5 × 10.5 in: small flat goods such as accessories, cosmetics, stationery and small boxes.
- 9.5 × 12 and 10 × 13 in: a folded t-shirt, a top, leggings or a handful of small items packed flat. This is why 10 × 13 is the default.
- 12 × 14.25 to 15 × 18 in: sweatshirts, a few shirts together and other soft, bulky goods.
- 19 × 23 and 19 × 24 in: jackets, blankets, towels and anything thick.
Thickness matters as much as width and height. A bulky item bulges the film and eats into the usable length, so a stack that looks like it fits on a table can still be too big once it is inside.
How to pick yours
Pack the product the way it will really ship (folded, in its own bag, with any insert), then measure its flat width, its flat height and how thick the stack is. The usable width should beat the product's width by about half an inch so it slides in without a fight, and the usable height should clear the product with room for the seal.
If you land between two sizes, go up one. A mailer that is slightly too big ships fine. One that is slightly too small gets forced shut and tends to give way at the seam.
What if none of the standard sizes fit?
You are not stuck with the list. TWOFORM designs mailers at custom sizes anywhere from 100 × 130 mm to 500 × 760 mm (3.9 × 5.1 in to 19.7 × 29.9 in), so a product that sits between two stock sizes can get a mailer drawn to its exact measurements.
Frequently asked questions
What is the most common poly mailer size?
10 × 13 inches (254 × 330 mm). It holds a folded t-shirt, which is the most common thing people ship.
Do poly mailer sizes include the flap?
No. The size is the outside width and height with the flap not counted.
What size poly mailer fits a t-shirt?
10 × 13 inches is the usual answer for one folded t-shirt. A heavier tee, or two together, usually moves you up to 12 × 15.5 inches.
What is the biggest standard poly mailer?
19 × 24 inches (483 × 610 mm), which is built for jackets, blankets and other bulky goods.
Can I get a poly mailer size that is not on the list?
Yes. TWOFORM designs mailers from 100 × 130 mm up to 500 × 760 mm.
Ready to try it? Design your own mailer in TWOFORM. Related reading: standard bubble mailer sizes and how to measure your packaging.