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  • Writer's pictureBinin

Everything to do With Poly Mailers

What is a poly mailer?

While not everyone knows the poly mailer by that name, nearly everyone who has purchased clothing online will have come into contact with these. The poly mailer is the convenient plastic bag that items can be shipped in. And the great thing? Not only do big companies utilize them, but they are also a wonderful option for resellers to ship their items. Because they are cheaper and less bulky, poly mailers should be every reseller's go-to when it comes to owning and utilizing their own shipping supplies. So, read on to find out everything to do with poly mailers from sizes to cushioning and designs!

Common Sizes

To best utilize the space of your poly mailer, you must know what size to use! When shopping for them, the vast amount of size variation can be overwhelming, so here are the Top 3 sizes that we see as the most common and helpful!

Common sizes include:


Small 6" x 12"

Medium 10" x 13"

Large 14.5" x 19"


Great for smaller items

This is the normal size of poly mailer. It can fit most things and is the most common.

Great for bigger and bulkier items.


Baby socks, jewelry, cosmetic items, a deck of cards, phone cases, etc.

2 T-shirts, 2 pairs of leggings, children's shoes, 1 pair of jeans, etc.

2 hoodies, 1 pair of jeans, 3 dress shirts, larger books, 4-5 rolled shirts, etc.

How to Calculate Poly Mailer Size

While the Top 3 sizes are good staples to have in you mailing supplies, the true best way to use poly mailers is to have the perfect size for the item you are shipping - not too big or too small. To do this, you need to fold or arrange your item in the way you would be shipping it and be able to measure it! Then you can use this formula to get the best poly mailer sizes:

Poly mailer size ↓ ↓ Item's measurements

Length = length + height + 2"

Width = width + height + 1"

After you determine the best size poly mailers for your needs, you also want to determine the thickness, often referred to as "mil" or "M." These can go up to 10 mil, but we recommend the industry standard 2.5 mil. You can increase the mil size if you find it necessary, but if you go lower than 2.0 then you may risk the bag being too flimsy.


Keep in mind, that if you are shipping something that is fragile, you're going to have to account for the extra padding. This could come in the form of your own bubble wrap, or you could buy cushioned poly mailers. Either way, cushioning will decrease the inner volume. So, generally, just increase the size of your poly mailer by 1/4" to 1/2" to account for the extra padding.

A Few Things to Keep in Mind...

Different reselling platforms may have different specifications or rubrics as to size and weight, so make sure that you know those for whatever platform you are selling on. The other thing, is that while too big poly mailers are not ideal, bigger is always better than smaller. A smaller item can fit into a bigger bag, but if the poly mailer is too small it is rendered useless. Also, you might not need to use your own poly mailer if shipping USPS Priority (read our blog about Poshmark shipping and free shipping supplies!).

Make it Your Own!

You can always stick with the simpler, cheaper poly mailers. But, if it is a part of your business to have cute packaging, you can get poly mailers in all colors and patterns! Additionally, you can make poly mailers your own by getting your brand or logo printed onto them. We hope that this post has you feel more confident about your ability to use poly mailers, and that you have fun with your shipping experiences!

Happy reselling!

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