How to Choose the Right Poly Mailer Size for Shipping

Poly mailer, also known as a courier bag, is a type of mailer bag made of polyethene film or plastic. Because it is both durable and lightweight, this mailing bag is an excellent shipping solution for online businesses.

When it comes to selecting the right poly mailer size for your product, we understand that it can be difficult for any online seller, especially those who are new to the business. Sometimes, it’s hard to visualise whether your product can fit perfectly into the poly mailer.

This is our guide to determining the best size for your poly mailer as well as those looking for the best size for Ninja Packs.

We hope this article sheds some light on how to pick the best poly mailer size for your product. Let’s have a look at it!

#1. Measure your product.

Measure product

This step is a no-brainer but it is necessary before you start purchasing your poly mailer online. Finding the right poly mailer size is more than just you placing your product on top of the poly mailer. It involves a simple calculation, but we will get to the bottom of that later.

What you should do first is to measure the length, width and the height your product. We will use a book for an example.

Start by measuring the product in millimeters using a ruler or measuring tape. Lay your product on the smooth surface to help your measurements become more accurate.

Here’s the final measurement of the product.
139.7 mm (Width) x 208.28 mm (Length) x 20.32 mm (Height)



#2. Calculate the minimum width and length for poly mailer size

Next, calculate the minimum width and length size for the poly mailer based on the formula below.

Formula to calculate the minimum length of the poly mailer.

The length of object + the height of object + double the height + Add 1/4 inch
208.28 mm + 20.32 mm + 20.32 mm + 6.35 mm
= 255.27 mm Minimum length of poly mailer


Formula to calculate the minimum width of the poly mailer.

The width of the object + the height of the object + Add ¼ inch
139.70 mm + 20.32 mm + 6.35 mm
= 166.37 mmMinimum width of poly mailer


Based on the calculation above, 255.27 x 166.37 mm is the minimum size for your poly mailer.

#3. Find the right size of poly mailer

Now that we have the minimum size for poly mailer, you can use it to find the right mailer size for your product.

Now, let’s find the right poly mailer with Ninja Packs by referring to the table below.

Ninja Pack sizes

The best Ninja Pack size dimension for the product would be S size in 320mm x 250mm.

At a first glance, you might feel like the poly mailer may be too big for your product.

However, a large size mailer is preferable to a small size mailer giving much room and space for your product to fit inside the poly mailer.

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