Are Bubble Mailers Considered Packages?

Whether a bubble mailer is technically considered a package depends on if it's thicker than 3/4 inches with your items inside
bubble mailers considered packages
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When it’s time to send out products, you’ve typically got two choices for packaging: boxes, or envelopes. Bubble mailers are one of the most popular envelopes for sending products…but did you know that USPS may not technically consider bubble mailers as packages if they aren’t thick enough?

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Bubble Mailers and Envelopes are Considered Packages When They’re 3/4 Inches Thick or More

USPS will only accept bubble mailers as packages if their total thickness is 3/4 of an inch or more. This applies not when the bubble mailer is empty, but when the contents of your shipment are inside. As long as the total thickness of your mailer is at least 3/4 of an inch, you’ll be able to use any of the USPS shipping services to send it. One of the most popular ways to ship bubble mailers like these with the Postal Service is USPS Ground Advantage Service.

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What Do I Do if My Mailer isn’t 3/4 of an Inch?

If your mailer is less than 3/4 inches think, then you’ve got what USPS calls a “flat” envelope. USPS requires you to mail flats instead of ship them, since they’re too thin to be considered actual packages. Therefore, you’ll need to send these out using good old-fashioned stamps for First-Class Mail. USPS technically makes more money from their mail products than their shipping products, so the workers at your local Post Office won’t hesitate to classify a thin envelope as something that needs to be sent via the mail, rather than with one of the USPS shipping services.

Something to keep in mind is that regular First-Class Mail service doesn’t include any kind of tracking, whatsoever. If you’d like to track your envelope the same way you can track a package, then you’ll need to purchase Certified Mail service at your local Post Office.

How Many Stamps Do I Need for Flat Envelopes?

When sending a flat envelope, each Forever First-Class Mail stamp covers enough postage for one ounce. Letters that weigh more than 1 ounce require additional ounce stamps on top of your first Forever Stamp. For instance, let’s say you’re sending a flat envelope that weighs two (2) ounces. In this case, you’ll need one Forever stamp and one additional ounce stamp. If your envelope weighs three (3) ounces, you’ll need one Forever stamp and two additional ounce stamps.

If your letter hits the maximum amount of 3.5 ounces, USPS will require a total of four stamps (one Forever and three additional ounce stamp), since that extra half-an-ounce needs its own postage stamp to cover it.

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  1. Stephen

    Shame they crack down on bubble envelopes at package rate, but they do very little about the huge amount of counterfeit Chinese stamps stole sold to this day very easily, Temu, AliExpress, anywhere China. Don’t kid yourself it’s because of all the counterfeit stamps is why the USPS upping price again.

  2. Gloria Smart

    9.5 x 14.5 poly padded envelope weighs 6.1 Oz, how many forever stamps. Padded envelope is less than 3/4 in thick.

    • TN

      Depends on where it’s going. Poly Padded Envelope = Package. Pkg rates depend on distance from where you are mailing it from. Use the online calculator at and put in the zip code. But it’s gonna cost you well over $4 no matter where it goes, even local. That’s a lotta stamps.

  3. Jordan

    I have a small item with dimensions of 1″ x 1″ x 1.75″
    It weighs 1.1 oz. How should I send this? Thinking a padded envelope.

    • TerraFirmaTX

      It’s going to be a package no matter what because of the thickness. So you can put it in whatever you like: small box, padded envelope, it’ll cost the same.

  4. Deb

    I have a small (5 x 7) padded envelope less than 1/2 inch thick and weighs < 1 oz. I put 2 Forever stamps on it. The USPS returned it to me a month later stating that postage due is $3.92. The other identical envelope I mailed at the same time was NOT returned to me. What gives??

    • TN

      99% of post offices consider all bubble mailers to be packages. Period. The other one? You got lucky….

  5. Beverly Albano

    I have a 10.5 x 16 padded envelope.
    How much to mail this?

    • k

      16″ is over the maximum length for first-class mail. It needs to be sent as a package

  6. TN

    This is BS. Every post office in the DFW area says ANY BUBBLE MAILER REGARDLESS OF SIZE MUST BE SHIPPED AT PACKAGE RATES, which start at $3.32 for commercial rate.

    • Daniel Boone

      DFW is the worst, no one knows the actual USPS policy; and then they won’t even listen to you once you explain it.

      • TerraFirmaTX

        Seems to be nation-wide now. I’ve had mail returned from other locations across the country for more postage, even stuff that should’ve been (and usually is) fine in a letter envelope (like a piece of ribbon lol).


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