Last Updated: Jul 25, 2022 2 min read

How to Calculate Poly Mailer Sizes for Shipping in less than 30 Seconds

How to Calculate Poly Mailer Sizes for Shipping in less than 30 Seconds

Shipping products to customers using poly mailers can save on shipping costs and provide a flexible means in which to wrap the product without needing a bulky or odd-shaped box. Unfortunately, it’s not always clear what size poly mailer to use for a given product. Here’s how to calculate poly mailer sizes for shipping.

Figuring out what size poly mailer to use is simple once you know what parts of the product to consider and why.

Poly Mailer Size Calculator

Here’s a handy calculator to determine the ideal poly mailer size for your next shipment. Input the product’s length, width, and height below.

Enter the product dimensions:

Minimum mailer size: Length: ? in. Width: ? in.

My Favorite Bubble & Poly Mailers

They’re built well, the price is fantastic, and they come in several sizes:

Poly: 10×13, 12×15.5, 14.5×19, 19×24, 24×24
Bubble: 6×10, 8.5×12, 10.5×16

You can also order most of these sizes from your local office supply store–and find smaller quantities in-store for immediate fulfillment needs, but will likely pay a lot more.

For the really odd sizes, try the Scotch Flex & Seal Shipping Roll.

The Formula to Calculate Poly Mailer Sizes

The general formulae for determining poly mail size are these:

Length: product length (in) + product height (in) + 2"
Width: product width (in) + product height (in) + 1/2"

Looking at these two formulas, a pattern emerges and is ultimately what decides the minimum size.

Sticking a product into a poly mailer will stretch its opening. Since a poly mailer itself isn’t stretchable, the maximum amount of surface area it can cover will never change. The product’s height will expand the mailer accordingly. This is why we have the heigh in both dimensions. The taller the product, the wider the poly mailer needs to be.

We add 2″ to the length to account for the flap and 1/2″ to account for deviations in measurements by manufacturers, extra room for maneuver the product into the poly mailer, and if we’re using a bubble mailer, specifically, accounting for the thickness of the mailer itself.

READ THIS NEXT: How to save money on USPS shipping.

If, when calculating this on your own you end up with a 1/2″ result, round up to the next full inch. Having a too-big mailer is much preferred over a too-small mailer.


The Seller Journal may receive a commission from purchases made through links in this post.
Click here to learn more about how we treat affiliate links and content that contains them.