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Right-Size Your Sustainable Packaging

Right-Size Your Sustainable Packaging

Oct 5th 2021

Once you’ve figured out what kind of  sustainable packaging you’ll be using to ship your goods, the next question is: what size(s) do I need?

Why does size matter so much? The first answer is obvious - your packaging solutions need to be large enough to securely fit your orders in them.

Even beyond the obvious fact that your packaging has to be large enough to ship what you need to send, there are also a few reasons why you want to avoid making them too big, with the aim of getting to just the right size for each shipment wherever possible.

  • Sustainability: By making your packaging as small as possible (while still meeting your functional needs), you are reducing the amount of material needed. Minimizing the amount of material used (aka “source reduction”) should actually be the very first step in any sustainability strategy.
  • Cost: Smaller packaging is less expensive, which makes sense as less material is needed. It is also lighter, making it less expensive to ship to you, and to your customers.
  • Shipping rate efficiency: In some cases, going with a smaller size can help your parcels fall into a lower shipping rate. For example, USPS classifies a “letter” as anything that is 3.5-6.25” in length by 5-11.5”” in height and up to 0.25” in thickness. If you’re debating between our smallest rigid mailer and a larger one, the smallest one will get you in the “letter” shipping rate. Similarly, the USPS uses the term “flats” to describe any large envelope that has one dimension greater one of the following: 6.25” in height, 11.5” in length, or 0.25” thick. But flats can be no more than 12” in height and 15” in length and 0.75” in thickness. Our 12x15” Paper Apparel Mailer is a great “USPS Flat” solution, so if this size works for your business, consider it instead of a larger version.
  • Customer experience: We’ve all experienced the #excessivepackaging #shippingfail of having a huge box arrive with the tiny product you ordered inside. Right sizing your packaging goes a long way in creating a more thoughtful customer experience (and yes, these small details do get noticed!).

Eco-Friendly Packaging: How to Measure for the Perfect Fit?

Great! So how do you actually measure your products and use those measurements to find the best sized mailer or box?

  • Step 1: Lay the item(s) you need to ship on a table and measure an “imaginary boundary” around it to get the length, width and height.
  • Step 2: Add a fitting allowance around these dimensions. If you want a snug fit, add 0.125 to the length and width for boxes, and 0.25 for mailers. If your item is thick (0.125" or more) and you plan on using a flat (non-gusseted) paper mailer, add at least 0.5 to your dimensions. If you want to make sure there is room for void fill in a box, add even more around the boundary. Also allow for any cushioning around the product for fragile items, up to 2" around all sides. Need some recommendations? Just reach out to our support team at [email protected].
  • Step 3A: Map these dimensions, with the cushioning included, to your mailer or shipping box. For shipping boxes, this is easy! Our boxes are custom cut to size, so you can input your dimensions and get the box size you need. Gusseted mailers expand to a set thickness, so if you are shipping thick, bulky goods (like a jacket), consider these options, available in our Kraft, Paper Apparel and EcoX Mailers. Go with the smallest size in the mailer style you need, that is at least as large as the boundary you measured (with the fitting allowance included). 

Note that our listed dimensions for boxes and mailers are different. Box dims refer to the interior dimensions, and most mailer dims refer to the exterior dimensions (interior dims are listed in a chart on the bottom of each product page).The exception is our Bubble Mailers whose stated dimensions refer to the interior dimensions.

If your orders are very varied, a single size box or mailer won’t work well for you. In these situations, keep the right variety of mailers and boxes on hand, and match each shipment to the right package, in a way that ensures protection and functionality while minimizing the size and source materials used.

Right Sizing In Action

In the following example, a company is looking to find  100% recycled poly mailers for t-shirts ranging in size from Small to Large. The t-shirt shown here is large, with dimensions of 4x8x2”. A 6x9” poly mailer is too small. While the company could choose between the 7.5x10” or the 9x12”, they have chosen to go with the 7.5x10” because it is the most material and cost efficient.

It is important to note that poly mailers are much more durable and flexible than paper mailers, allowing you to opt for a tighter fit with these than you might if you were shipping in paper.

In the following example, a company is looking for a cost and material efficient way to ship a beautiful wall piece. In this instance, the 12x15”  Paper Apparel Mailer allowed for a snug but secure fit.

Common Mailer Sizing Examples

The following chart provides some ideas for how to match common products with mailer sizes. As products across different companies are never exactly the same, use this guidance as a starting point, not as a substitute for taking the above steps to right size your packaging.


Poly Mailers Kraft Mailers Apparel Mailers EcoX Mailers Padded Mailers Bubble Mailers
Sweater 12x15.5", 14.5x19" 12.5x19" 12x15", 10.5x4x19" 14.5 x19, 19x24", 10.5x4x19"
T-shirt 9x12" 6x2.5x12" 10x13" 9x12", 6x3x12"
Dress shirt 10x13" 6x2.5x12", 9.5x14.5", 10.5x16" 10x13" 10x13", 12x15"
Two shirts 10x13" 9.5x14.5" 12x15" 10x13", 12x15"
Three shirts 12x15.5" 12.5x19" 10.5x4x19" 19x24", 9.5x3x16"
Dress or jeans 12x15.5" or 14.5x19" 12.5x19" 12x15" or 10.5x4x19" 19x24", 9.5x3x16", 10.5x4x19"
Socks, Baby Clothes, Masks 6x9" 6x10", 6x2.5x12" 7x9" or 10x13" 6x9", 7.5x10"
Essential Oils (1 small bottle) 6x9", 7.25x11" 4x6.75''
Essential Oils (2 small bottles) 8.5x11" 6.5x8.75'', 10.5x15"
Cosmetics 6x9", 7.25x11" 4x6.75'', 6.5x8.75''
Jewelry 6x9", 7.25x11" 4x6.75'', 6.5x8.75''
Soap 6x9", 7.25x11", 8.5x11" 4x6.75'', 6.5x8.75''
Small accessories 6x10", 6x2.5x12" 7x9", 10x13" 6x9", 7.5x10", 6x3x12" 6x9", 7.25x11", 8.5x11" 4x6.75'', 6.5x8.75''
Backpacks, purses 14.5x19", 19x24", 24x24" 10x4x19" 10.5x4x19" 10.5x4x19" 14.25x19"

Order Free Samples To Test Your Packaging!

EcoEnclose is proud to offer free samples to help you test different sizes before placing your final order. Try sizes across different mailers and test a variety of custom corrugated samples as well. We do ask that you pay for shipping on these. Order your  free samples today