How Many Stamps for a Bubble Mailer?

Sending a bubble mailer with postage stamps is an easy and cost-effective way of shipping light, small packages. Not all bubble mailers can be sent with the same postage, though. Here is a step-by-step guide on when and how to put bubble mailer stamps on bubble mailers correctly.

Can You Put Stamps on a Bubble Mailer?

Yes, you can definitely put stamps on a bubble mailer. Just think of stamps as postage money. As long as you put stamps to cover the total amount of shipping, your bubble mailer will be accepted by the United States Postal Service (USPS).

But it's not quite so simple as just affixing a single Forever stamp and sending it on its way. Bubble mailers almost always count as packages, not letters, so they cost more to mail. It's worth it to calculate the correct postage so your item arrives without delay or postage-due fees to the recipient.

We’ve developed Bubble Mailers that are in compliance with USPS requirements, making them ideal for sending with stamps while adequately protecting your items.

When to Use / Not Use Stamps to Ship a Bubble Mailer

Stamps are convenient, but they're not necessarily the best choice. Following is a convenient guide to help you make that choice.

Use stamps when:

• The bubble mailer is under 3/4-inch thick.

• It weighs less than 13 oz.

• It's still flexible (bendy).

• To mail small floppy objects like papers, jewelry, or clothes.

Avoid using stamps when:

• The mailer is rigid or contains bulky items.

• It exceeds the weight or thickness limits for First-Class Mail.

• It should be traceable or show proof of delivery (stamps do not track).

• It has something worth value or urgency (sending with a label may be a better choice instead).

• Sending overseas: Global mail comes with complicated customs requirements and postal fees that cannot be handled by stamps alone.

USPS Services That Apply to Bubble Mailers

The bubble mailer you send through the mail will receive delivery service from one of the following USPS service categories.

• USPS Ground Advantage™: This service provides the most affordable and widely used delivery option for bubble mailers. The service accepts packages that weigh up to 70 pounds and provides tracking information through Post Office label purchases and online transactions.

• First-Class Mail® (Large Envelope/Flat): A bubble mailer qualifies as a "flat" when it exhibits flexibility and maintains a consistent thickness of less than ¾ inch. The reality is that almost all bubble mailers lose their qualification when carrying contents inside. The postal service will apply the elevated package fee to mailers which have rigid structures  or uneven surfaces or exceed the ¾ inch thickness measurement. You should always treat your bubble mailer as a package for rate calculations.

• Priority Mail®: If you need your package to arrive faster (typically 1-3 business days), Priority Mail is a great option. It costs more but includes tracking and up to $100 of insurance.

• Media Mail®: Only for approved educational materials like books, DVDs, and printed music.

• Parcel Select Ground®: Budget-friendly option for heavier packages, but slower delivery.

How to Calculate Stamps for a Bubble Mailer

Weigh It Accurately

Guessing the weight is the number one reason mail is returned or arrives with postage due. Use a digital kitchen scale or a postal scale for an accurate reading. You must weigh the mailer after all packing and sealing operations have been completed.

Tip: Picking a mailer with the right thickness will save on postage charges. For lightweight yet protective shipping options, check out JiaroPack’s 4x8 bubble mailers and 6x10 bubble mailers. Reliable USPS options for shipping smaller items like jewelry, gadgets, and documents.

Measure Thickness & Rigidity

The outcome of this phase will decide if your mailer qualifies as a “flat” or transforms into a “package”.

• Is it more than ¾-inch thick at any point?

• Is it rigid or inflexible?

• Is it lumpy or not uniformly thick?

If you answered “yes” to any of these, you have a package. The majority of bubble mailers that contain products belong to this group. 

Pick the Correct USPS Category

Based on the step above, you’ll almost certainly be shipping your bubble mailer as a USPS Ground Advantage package. Do not attempt to send it through the mail as a letter or flat unless you have verified it fulfills all the required flexibility and thickness standards.

Check the Current Rates

Postage rates can change, so always check for the USPS Price List (Notice 123) or Shipping Rates Calculator to get the most accurate postage rates. The "USPS Ground Advantage" table requires your attention. The delivery cost depends on the package's weight and the distance from the origin point to its destination.

Do the Math or Use a Postage Calculator

• One Forever Stamp covers $0.68 (as of 2025).

• If your mailer qualifies as a flat and weighs 2 oz, you’ll need $1.59 (1 Forever + 1 additional ounce stamp).

• If it’s a 6 oz parcel, you may need $4.75, which translates to 7 Forever stamps.

For the easiest and most accurate method, use the official USPS Postage Price Calculator on their website.

How to Send a Bubble Mailer With Stamps

Affix Stamps Correctly

• Stamps need to be placed precisely in the upper right area of the envelope.

• The stamps must keep their original shape and position without any contact with each other.

• Calculate the total postage value that corresponds to your selected mailer category. 

Choose Drop-Off Method

• Mailboxes function to receive smaller packages that have the correct amount of postage. 

• The Post Office Drop Slot provides a better solution for sending heavy packages. 

• The service directs users to deliver their packages to clerks when they need help with their delivery process. 

• Your mail carrier will receive your outgoing mail when you have any to send.

Bubble Mailer Size & Weight Limits

Reference: USPS Size & Weight Guidelines

Checklist Before You Mail

✅ Weigh your mailer and round up to the nearest ounce

✅ Measure thickness and flexibility

✅ Determine USPS category (flat or parcel)

✅ Use USPS Postage Calculator

✅ Affix the correct number of stamps

✅ Drop off at a safe and proper location

✅ Optional: Record tracking manually if you’re adding that separately

FAQs

How many stamps for a 6x9 bubble mailer?

A 6x9 bubble mailer requires two Forever Stamps for delivery when its weight stays below 1 ounce. The shipping cost for heavier mailers increases, so users must verify their package weight and USPS rates before sending anything. 

How many stamps for a padded envelope?

A padded envelope is usually treated as a package by USPS. The mailing cost needs two Forever Stamps when the weight stays below 1 ounce. The postal service needs users to verify their package weight because heavier padded envelopes need more postage according to USPS rates.

What happens if I don't put enough stamps on my bubble mailer?

The USPS will likely send it back to you for more postage or forward it to the addressee with a "Postage Due" notice, meaning they'll need to pay the difference in order to receive their mail.

Can I just use one Forever Stamp?

It occurs almost never. One Forever Stamp will cover only a standard one-ounce letter. A bubble mailer is an envelope, and always will be much more expensive.

Can I get a tracking number if I use stamps?

No, tracking is something that comes with a barcode that is attached when you are ordering a shipping label online or at the Post Office. Stamps applied do not come with a tracking number. If you need tracking, you will need to purchase postage at the counter or online.

Can I send international bubble mailers with stamps?

Yes, but you will have to apply Global Forever stamps or international rate stamps, and the package must be international-compliant.

Conclusion

Mailing a bubble mailer in the post with stamps is an entirely valid option for light, low-value items when you don't need tracking. The secret to success is to treat your mailer as what it actually is: a package. By weighing it correctly, calculating the right USPS Ground Advantage rate, and affixing the right number of stamps, you can send your item off confident in the knowledge that it is going on the right track. If in doubt, or if carrying heavier and more valuable items, it is always safest to simply nip down to the Post Office.