An empty bubble mailer weighs about 0.3 to 3 ounces, depending on its size and outer material. A common 6 × 9 inch (#0) poly bubble mailer weighs roughly 0.4 to 0.5 ounces, while a large #7 kraft mailer can reach about 3 ounces.
That small number matters because light parcels are priced by the ounce. Add the mailer, the item and any tissue or inserts together, and the total decides which USPS weight tier you pay for. Below are typical weights by size, then how the packed weight is billed.
How Much Does a Bubble Mailer Weigh by Size?
Bubble mailers use a numbered size scale, and weight rises steadily with size. Exact sizes vary a little between manufacturers, so check the dimensions printed on the case. The ranges below are typical empty weights.
| Size | Approximate dimensions | Poly mailer weight | Kraft mailer weight | Common uses |
|---|---|---|---|---|
| #000 | 4 × 8 in | 0.3–0.4 oz | 0.5–0.7 oz | Jewelry, cards, USB drives |
| #0 | 6 × 9 in | 0.4–0.5 oz | 0.8–1.2 oz | Phone accessories, small cosmetics |
| #1 | 7 × 12 in | 0.6–0.8 oz | 1.0–1.4 oz | Paperbacks, small apparel |
| #2 | 8.5 × 12 in | 0.7–0.9 oz | 1.2–1.6 oz | Documents, thin clothing |
| #4 | 9.5 × 14.5 in | 1.0–1.3 oz | 1.5–2.0 oz | Hardcover books, tablet cases |
| #5 | 10.5 × 16 in | 1.2–1.5 oz | 2.0–2.5 oz | Folded garments, multi-item orders |
| #7 | 14.25 × 20 in | 2.0–2.5 oz | 2.5–3.0 oz | Bulky soft goods |
To check a size against your item, measure the item’s length, width and thickness first; our guide on how to read dimensions shows the order to read them in.
Why Do Poly and Kraft Bubble Mailers Weigh Different Amounts?
A poly bubble mailer has a thin plastic film outside and bubble lining inside, so it is the lightest padded option. A kraft bubble mailer bonds paper to the bubble layer, which adds stiffness and roughly 20 to 50 percent more weight at the same size. Paper-padded mailers stuffed with shredded fiber are heavier still.
Smaller details add a little too. A self-seal strip, double bubble lining or a tear strip can add about 0.1 to 0.2 ounces, and two mailers of the same size from different brands can differ by a similar amount. If you ship in volume, weigh one empty mailer from each new case instead of trusting the listing.
How Much Do the Item and Inserts Add?
The mailer is usually the smallest part of the total. The billable figure is the gross weight of everything inside the sealed mailer, as our guide to gross weight vs net weight explains. Typical additions:
- Tissue paper: about 0.1–0.2 oz per sheet
- Packing slip or invoice: about 0.2 oz per sheet of printer paper
- Thank-you card or sticker: about 0.1–0.3 oz
- Small piece of bubble wrap: about 0.3–0.5 oz
- Shipping label: about 0.1 oz
For common contents, our weight guides for a book and a pair of shoes give typical shipping weights to add to the mailer.
How Does Bubble Mailer Weight Affect USPS Pricing?
A padded mailer with a three-dimensional item inside is normally mailed as a package, usually by USPS Ground Advantage. Ground Advantage, which replaced First-Class Package Service in July 2023, prices packages under 1 pound in ounce tiers (up to 4, 8, 12 and 15.99 ounces) and rounds anything heavier up to the next whole pound. It delivers in 2–5 days and includes USPS Tracking.
| Item weight | Mailer used | Packed total | USPS Ground Advantage tier |
|---|---|---|---|
| 3.4 oz | #000 poly (0.4 oz) | 3.8 oz | Up to 4 oz |
| 3.4 oz | #0 kraft (1.0 oz) | 4.4 oz | Up to 8 oz (one tier higher) |
| 7.2 oz | #2 poly (0.8 oz) | 8.0 oz | Up to 8 oz |
| 14.8 oz | #4 kraft (1.8 oz) | 16.6 oz | 2 lb (over 1 pound rounds up) |
As the table shows, the mailer choice alone can move a shipment into the next tier. When a total is within a few tenths of an ounce of a break, switching from kraft to poly or dropping an insert keeps it in the lower tier. Mailers rarely trigger dimensional weight at USPS, which applies it only to packages over 1 cubic foot, but UPS applies dimensional weight to every package, so a thick #5 mailer can bill at several pounds with UPS.
A flat, flexible mailer of uniform thickness can sometimes go as a First-Class Mail large envelope instead, but only up to 15 × 12 inches, 3/4 inch thick and 13 ounces. Our guide on whether bubble mailers are considered packages explains where that line falls, and our guide to USPS bubble mailer shipping costs covers how the tiers are priced.
How Do Bubble Mailers Compare With Boxes on Weight?
A bubble mailer is much lighter and thinner than a box of similar footprint, which is why it is the default for small, non-fragile items. A small corrugated box weighs several ounces before any void fill, and its depth adds cubic inches. The trade-off is protection.
| Packaging | Typical empty weight | Protection | Best for |
|---|---|---|---|
| Plain poly mailer | 0.1–0.3 oz | Low | Clothing and soft goods |
| Poly bubble mailer | 0.3–2.5 oz | Medium | Accessories, cosmetics, small electronics |
| Kraft bubble mailer | 0.5–3 oz | Medium | Books, items that benefit from a stiffer shell |
| Small corrugated box | 3–6 oz | High | Glass, ceramics and anything that can crush |
Use a box when the item is fragile, has sharp corners that could puncture film or is part of a multi-item order that needs separation. For bulky orders, our guide on how to calculate cubic inches shows when a box crosses the 1-cubic-foot line.
How Do You Weigh a Bubble Mailer Shipment Accurately?
Seal the mailer with everything inside, then set it on a digital kitchen or postal scale that reads to 0.1 ounce. Round up to the next tier, never down, and weigh again if the total is close to a break. Our step-by-step guide on how to weigh packages at home covers scale setup.
Once you have the weight, you can compare live USPS and UPS rates for your mailer in the ParcelPath rate calculator. ParcelPath is free, with no subscription or per-label fee, offers up to 89% off USPS retail rates and supports free USPS pickups. More ways to trim postage are in our guide on how to ship for less.
Frequently Asked Questions
How much does a 6×9 bubble mailer weigh?
An empty 6 × 9 inch (#0) poly bubble mailer weighs about 0.4 to 0.5 ounces. The kraft paper version of the same size is heavier, at roughly 0.8 to 1.2 ounces. Add the item, any inserts and the label to that figure to get the weight you enter for postage.
How much does a bubble mailer weigh in grams?
Most empty bubble mailers weigh between about 8 and 85 grams. A small #000 poly mailer is around 9 to 11 grams, a #0 poly mailer about 11 to 14 grams, and a large #7 kraft mailer can reach roughly 70 to 85 grams. Brands vary by a few grams at the same size.
Do I need to include the bubble mailer in the shipping weight?
Yes. USPS and UPS bill the total weight of the sealed package, so the mailer, the item, tissue, inserts and label all count. Leaving out even a 1-ounce kraft mailer can push a shipment into the next USPS Ground Advantage ounce tier and lead to an underpaid label.
Is a poly bubble mailer lighter than a kraft one?
Yes. A poly bubble mailer is typically 20 to 50 percent lighter than a kraft bubble mailer of the same size, because it uses plastic film instead of a paper outer layer. On a 6 × 9 inch mailer that is roughly 0.4 to 0.5 ounces for poly versus 0.8 to 1.2 ounces for kraft.
Sources
- USPS Ground Advantage service overview
- USPS Domestic Mail Manual 223: dimensional weight rules for parcels over 1 cubic foot
- USPS Domestic Mail Manual 101: physical standards for letters, flats and parcels
Part of our How to Weigh Packages at Home guide. Related: Weighing Packages for Shipping, Gross Weight vs Net Weight, How Much Does a Tire Weigh.
