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Poly Mailer Size Calculator

Enter a product’s dimensions and how much it squashes to find the smallest standard poly mailer it fits in — so you do not pay to ship air or split a seam with a mailer that is too tight.

Item
in
Folded size, if it is clothing.
in
in
How soft is it?

Results

Recommended poly mailer10 × 13 inNeeds at least 9.8 × 12.8 in inside
Minimum inside width9.8 in
Minimum inside length12.8 in
Packed thickness0.8 in (soft (T-shirts, fabric))
6 × 9 in
Too small
7.5 × 10.5 in
Too small
9 × 12 in
Too small
10 × 13 in
Fits ✓ smallest
12 × 15.5 in
Fits
14.5 × 19 in
Fits
19 × 24 in
Fits
24 × 24 in
Fits

Sizes are the inside width × length below the flap; check the exact inside dimensions from your supplier, as they vary by brand.

Poly mailers protect against moisture and scuffs, not crushing. Fragile items belong in a padded mailer or a box.

How it works

  1. Measure the item as it will be packed — folded, bagged or boxed.
  2. Enter length, width and thickness in inches.
  3. Choose how much it compresses when the mailer is sealed.
  4. Read the smallest standard mailer that fits and check the other sizes listed.

Formula

Packed thickness = thickness × (1 rigid · 0.75 semi-soft · 0.5 soft)
Inside width ≥ shorter side + packed thickness + 1 in
Inside length ≥ longer side + packed thickness + 1 in

A flat mailer has no gusset, so the item’s thickness is taken up from both its width and its length as the bag wraps around it. One inch of ease lets the item slide in and the flap seal. Standard sizes checked: 6 × 9, 7.5 × 10.5, 9 × 12, 10 × 13, 12 × 15.5, 14.5 × 19, 19 × 24 and 24 × 24 in. (inside, below the flap).

Example

A pair of folded jeans measuring 13 × 10 in. and 2.5 in. thick.

Inputs

Item length
13 in
Item width
10 in
Item thickness
2.5 in
How soft is it?
Semi-soft

Result

Recommended poly mailer14.5 × 19 inNeeds at least 12.9 × 15.9 in inside
Minimum inside width12.9 in
Minimum inside length15.9 in
Packed thickness1.9 in (semi-soft (folded jeans, bagged items))
Load this example into the calculator →

Why the right mailer size matters

Too small and the seams or flap adhesive strain in transit; too large and the item slides around and you may pay more if the carrier measures the package. The smallest mailer that fits with about an inch of ease is usually right.

For thick or boxy items a flat mailer bulges into a pillow shape. Past about 4 in. of packed thickness, a box or a gusseted (expandable) mailer usually ships better.

Frequently asked questions

What fits in a 10 × 13 poly mailer?

Items up to about 9 × 12 in. minus their thickness — for example a folded T-shirt or a pair of leggings.

What size poly mailer for a hoodie?

A folded hoodie is often about 12 × 10 × 3 in.; with soft compression that needs about 12.5 × 14.5 in. inside, so a 14.5 × 19 in. mailer.

Do poly mailer sizes include the flap?

Sizes are usually listed as width × length, and many brands quote the length without the flap. Check the supplier’s inside dimensions.

Should I use a poly mailer or a box?

Poly mailers suit soft, unbreakable goods. Rigid, fragile or bulky items travel better in a box.