The Ultimate Guide to Choosing Kraft Self-Seal Padded Mailers

Bubble mailers are complex to manufacture, and the construction and sealing process is susceptible to temperature and melting points and highly partial to the purity and consistency of virgin content. It took us a long time to get to this level of recycled content, but we’ve learned a lot. We are moving forward from here, constantly pushing up recycled content levels with each iteration to eventually get to 100% recycled content.

You may have found other recycled bubble mailer options if you’re looking for eco-friendly bubble mailers. We dug into these options as we developed our recycled bubble mailer and learned that their claims could be vague.

If you see a recycled mailer that claims 5%, 10%, and 30% recycled content, it is likely the case that “up to X% of the outer layer of the mailer” is made with recycled content. If this is the case, it would mean that the outer layer has an arbitrary amount of recycled content, based on what the manufacturer had as scrap from their recent production runs. More than likely, the bubble and capping layers (internal) of the bubble mailer are made with only virgin poly. Given this, a mailer stating 30% recycled content would have between 0% to 16% recycled content when looking at the entire mailer, and you wouldn’t know the exact recycled content in the particular bag you purchase get.

When looking for recycled bubble mailers, we recommend asking suppliers for a breakdown of recycled content by layer within their mailers. Confirm that the recycled content is consistent and verified, and consider asking them where their product is manufactured. These questions may sound like overkill, and we know companies aren’t typically trying to make misleading claims! They often take the information they receive from their supply chain at face value without asking hard questions. Because the supply chain for most items (especially packaging) starts in Asia, it is often impossible for them to verify claims. Finally, while the Federal Trade Commission has excellent guidelines for Green Marketing, there aren’t certifying bodies that verify recycled content claims (in the same way there are for things like Certified Organic and Certified Compostable). It is up to consumers to ask these hard questions to ensure sustainability innovation is genuine rather than greenwashing.

When it comes to padded envelopes and bubble mailers, one size does not fit all. In this post, we’ll cover the difference between padded and bubble envelopes, how to choose the best mailer, and the many padded envelope sizes on the market. Bonus: We’ll also touch on the history of Bubble Wrap! 🤯

Why Choose a Padded Envelope or Bubble Mailer

If you have something fragile you’re trying to ship or want extra peace of mind when mailing an item, choose a padded envelope.

Studies show that small packages are dropped, tossed, and handled 27 times in a one-way shipment. Without padding, items can slide around or fall out in the shipping process, sometimes causing irreparable damage. Placing your objects in a sealed padded envelope is a much sturdier and more secure way to pack and ship your valuable objects and products.

Padded envelopes are ideal for transporting important flat items—such as Blu Rays, CDs, books, and jewelry—securely. Packages can bounce around during the shipping process, so finding a durable, padded envelope means you don’t have to worry about your valuables breaking.

With so many opportunities for the objects you’re shipping to get damaged, using a padded envelope or bubble mailer is a no-brainer for important shipments.

Padded Envelope vs. Bubble Mailer

You may have seen these terms used interchangeably, but there’s a difference between padded envelopes and bubble mailers. When searching for padded envelopes, you’ll likely get results for both padded envelopes, bubble mailers, and poly bubble mailers.

Padded Envelopes

A padded envelope, or a padded manila envelope, is made of strong, durable material. They do not have Bubble Wrap lined inside. Padded envelopes are reinforced with additional paper or foam on the interior.

Bubble Mailers

Bubble mailers have a paper exterior with Bubble Wrap lined inside. They give added protection for delicate items. Bubble size will vary depending on the product. The larger the bubbles, the safer your package. (And the better the pop!)

Poly Bubble Mailers

When searching for bubble mailer options, you will likely come across poly bubble mailers too. Poly mailers are made with Bubble Wrap but are completely plastic with no paper exterior. The polymer gives added protection and more color options but the plastic makes it more challenging to write an address.

History of Bubble Wrap

🤫 Are you secretly reading this article to learn more about your favorite poppable shipping product?

While anyone in the shipping world, or anyone who simply loves to pop plastic bubbles, would consider Bubble Wrap to be the greatest innovation since sliced bread, the story of its unintentional creation may surprise you.

Bubble Wrap was invented by mistake in 1957 by Alfred Fielding and Swiss chemist Marc Chavannes. The two inventors were actually trying to develop a textured, three-dimensional wallpaper aimed at attracting young members of the Beat Generation. They tried putting two pieces of plastic shower curtain through a heat sealing machine. To their surprise and chagrin, what came out was a sheet of plastic with air bubbles trapped inside.

The two inventors continued working on their invention, trying to find some sort of application for Bubble Wrap. After a few unsuccessful years, Fielding and Chavannes decided to use it as packaging material. It was fortuitous timing as IBM had just created the 1401 Processing System and they were searching for a way to ship their fragile piece of computer equipment. 

Bubble Wrap soon became the favorite way to ship. And as for the irresistible desire to pop the bubbles? There’s no quaint origin story there; bubbles were made for popping!

✉️ Want more envelope-related history? Read Looking Past the Fold: A History of Envelopes.

How to Choose the Padded Envelope That’s Right for You

Durable Self Seal

A bubble mailer should self seal to ensure it stays closed. Besides, who wants to lick envelopes? (Maybe Larry🐶)

When choosing a padded envelope, ensure it has a strong, durable seal that’s self sticking.

✉️ Learn more about the many types of seals: A Lesson in the Different Types of Envelope Seals.

Paper or Plastic

Paper vs. plastic comes down to what you’re shipping and how delicate it is.

 Padded envelopes are typically made using only paper. While it’s often thick, quality Kraft paper that’s resistant to tearing or ripping, it can get wet. 

If you’re shipping something delicate, like jewelry or a CD, you may want packaging with more protection. Bubble mailers are made with Kraft paper on the outside and an interior lined with Bubble Wrap. Poly bubble mailers are fully plastic, so you’ll have Bubble Wrap protection and waterproof packaging.

When choosing between paper and plastic, consider how durable you need the envelope to be. Could it get wet? For plastic options, you’ll likely need a permanent marker to address the envelope.

Color or Plain

Poly bubble mailers come in all sorts of colors if you’re looking for something with a little extra flare. Custom bubble mailers can match your company branding, sending your package off in style.

If you want a more professional look for your mailer, opt for a white, black, or paper finish.

Envelope Size

The size of your envelope is the most critical aspect to consider before making your purchase. The envelope should always be larger than the document or object you are sending so nothing is crushed or folded. Be sure to allow for extra room. 

That being said, make sure your padded envelope or bubble mailer is not too much larger than your documents or objects. Bubble Wrap is non-adhesive, which means objects have the potential to slide around during shipping. The contents of your package should fit easily but securely within the envelope.

Padded Envelope Size Chart: Common Sizes 

Envelope Dimensions

Typical Usage

10 in. x 13 in.

●     Unfolded mailings about 9-3/4 in. x 12-3/4 in.

●     Large catalogs, photos, and reports

9 in. x 12 in.

●     Unfolded mailings on 8-1/2 x 11 sheets of paper

●     Promotional material, large cards, or brochures

●     Up to 60 sheets of paper

6 in. x 9 in.

●     Mailings around 5-3/4 in. x 8-3/4 in., or sheets of standard 8-1/2 in. x 11 in. folded in half

●     Promotional materials

●     Small catalogs, small magazines, programs, journals, or brochures

✉️ More on common business envelope dimensions in our article Business Envelope Dimensions: 10 Common Envelope Sizes Used at the Office. Read it for envelope dimension charts and uncommon envelope sizes used for QuickBooks, business forms, and taxes.

Bubble Mailer Size Chart: Common Sizes

Exterior vs. Useable Size

There are two dimensions to consider when selecting a bubble mailer. When you have an envelope lined with Bubble Wrap or a poly bubble mailer, the outside dimensions will differ from the interior dimensions. This difference is often referred to as exterior vs. useable size.

To choose the right size envelope, you need to consider the outside dimensions (exterior) for shipping costs as well as the inside dimensions (useable) so that your product will fit inside. Remember to leave enough room for your product to fit inside comfortably, but not too much room so that your product doesn’t bounce or slide inside the envelope during shipping.

While padded envelopes typically come in a few standard sizes, bubble mailers are produced in a wide range of sizes and can often vary depending on the supplier you purchase from. Even the height of the bubbles will play a role in envelope size. When in doubt, ask for a sample or buy a small amount that you can test before you make a bulk purchase. Below we’ve outlined a few bubble mailer sizes as well as their uses. Uliner has a mailer guide to determine the right size mailer if you are ordering from them.

Exterior Size

Useable Size

Typical Usage

12.5 in. x 19 in.

12.5 in. x 18 in.

●     Large catalogs, photos, and reports

●     Extra-large items such as textbooks, toys, clothing, and stationary

8.5 in. x 12 in.

8.5 in. x 11 in.

●     Unfolded mailings on 8-1/2 x 11 sheets of paper

●     Reports, catalogs, magazines, or journals

●     Larger items such as graphic novels and hardcover books

7.5 in. x 11 in.

7.5 in. x 10 in.

●     

Midsize items such as DVDs, books, or photos

6 in. x 10 in.

6 in. x 9 in.

●     

Midsize items such as Blu Rays, CDs, or photos

4 in. x 8 in.

4 in. x 7 in.

●     

Small items such as jewelry, writing utensils, or phones

✉️ Read our Envelope Size and Style Guide for more on envelope sizes, visual examples, and envelope terminology.

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