Bubble Mailer Size Chart: The #000 to #7 Decoder (Plus Poly Mailer Sizes)

Packaging Reference

Bubble Mailer Size Chart: The #000 to #7 Decoder (Plus Poly Mailer Sizes)

Bubble mailers use a standardized numbering system from #000 up to #7. This chart decodes each number into its outer size and approximate usable inner space, with typical contents. A poly mailer section follows for flat, non-fragile goods. Inner dimensions are approximate.

The bubble lining and sealed flap trim the usable inside: roughly a quarter to a half inch on width and about 1 to 1.5 inches on length (the sealed flap eats more), so the inside is always smaller than the size you order.

Bubble mailer sizes: #000 through #7

Outer size is the standard industry dimension for each number. Usable inner size is approximate, allow for the bubble padding. All dimensions width x length in inches.

Bubble mailer size decoder. Outer sizes are industry standard; inner sizes are approximate (width x length, inches).
Size Outer (W x L) Approx. inner Typical contents
#000 4 x 8 3.75 x 6.5 Jewelry, USB drives, keys, small electronics parts
#00 5 x 10 4.75 x 8.5 Cosmetics samples, cables, small accessories
#0 6 x 10 5.5 x 8.5 Phone cases, cards, seed packets, small booklets
#1 7.25 x 12 7 x 10.5 Paperbacks, jewelry boxes, cosmetics, small electronics
#2 8.5 x 12 8.25 x 10.5 DVDs, small hardcovers, folded T-shirts, sunglasses
#3 8.5 x 14.5 8.25 x 13 Trade paperbacks, tablets in sleeves, small apparel
#4 9.5 x 14.5 9.25 x 13 Hardcover books, folded garments, larger accessories
#5 10.5 x 16 10.25 x 14.5 Two-book bundles, shoes in flat boxes, mid-size apparel
#6 12.5 x 19 12.25 x 17.5 Larger apparel, framed prints, bulkier soft goods
#7 14.25 x 20 14 x 18.5 Large soft goods, small pillows, multi-item apparel orders
Rule of thumb: the usable inside of a bubble mailer runs roughly a quarter to a half inch smaller on width and about 1 to 1.5 inches smaller on length, since the sealed flap eats more than the side lining. When an item is right at the edge of a size, go up one number.
A note on #7: #7 has the widest cross-vendor variance of any bubble mailer size. Some non-Uline vendors run #7 around 14 x 18.5 to 19 inches outer rather than 14.25 x 20. If you are ordering right at the edge of the #7 size, verify the spec sheet for that specific supplier.

Poly mailer sizes and what fits

Poly mailers are lightweight, waterproof, and unpadded, best for soft, non-fragile goods. Sizes below are the flat outer dimensions (width x length, inches).

Common poly mailer sizes and typical contents (width x length, inches).
Size (W x L) Typical contents
6 x 9 Single tee, accessories, small soft goods, socks
9 x 12 Folded shirts, leggings, single garment, thin softcover
10 x 13 Hoodies, thicker apparel, small multi-item soft orders
12 x 15.5 Bundled apparel, sweaters, bedding pieces, plush items
14.5 x 19 Multiple garments, jackets, larger soft bundles
19 x 24 Bulky apparel, comforters, large soft-goods orders
Mil thickness is the real poly-mailer decision: poly mailers are sold by thickness in mils, not just size. Around 2.35 mil is the everyday standard for apparel and soft goods, while 4 mil heavy-duty is worth stepping up to for heavier items, sharp corners, or anything that could snag or tear in transit. Thicker film costs a little more but resists punctures far better.

How to use this chart

Lay your product flat and measure its width and length, then add a little slack so it slides in without straining the seal. For bubble mailers, match those numbers to the approximate inner size, not the outer size, so the padding does not squeeze the fit. For poly mailers, pick a size an inch or two larger than the item on each side so you can fold and seal cleanly. When a product is fragile, choose a bubble mailer; when it is soft and durable, a poly mailer is lighter and often cheaper to ship.

Frequently asked questions

What do bubble mailer numbers like #000 and #5 mean?
They are a standardized size code. Higher numbers mean larger mailers. #000 is the smallest common size at 4 x 8 inches outer, and #7 is among the largest at about 14.25 x 20 inches outer. Most suppliers follow the same numbering.
Is the size on a bubble mailer the inside or outside?
The listed size is the outer dimension. The usable inside is smaller, typically by a quarter to a full inch on each side, because of the bubble lining. Always size to the inner space for a good fit.
Bubble mailer or poly mailer, which should I use?
Use a bubble mailer for anything that needs cushioning, such as electronics, cosmetics, or books with corners. Use a poly mailer for soft, durable goods like apparel, where the priority is a light, waterproof wrap rather than padding.
How do I measure a bubble mailer?
Measure the outer width across the sealed sides and the outer length from the bottom seal to the base of the flap. The usable inner cavity is slightly smaller once the padding is accounted for.
Can I ship fragile items in a poly mailer?
Poly mailers have no padding, so fragile items need wrapping first or, better, a bubble mailer or a box. For anything breakable, choose padded protection over an unpadded poly bag.

Find the right mailer

Match your size to the collections below.

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Shipping something rigid or fragile that needs more structure? A corrugated box or branded mailer box may be the better call.

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Outer sizes reflect common industry standards; inner dimensions are approximate and vary by manufacturer. Confirm exact measurements against the specific mailer you order.