Measure the item in its packed shape, not flat, then add room for the side seams and adhesive closure. Test the thickest item in the batch and avoid stretching the mailer or forcing the seal. Use a box or padded mailer when the contents are rigid, fragile or need crush protection; compare poly mailers and boxes for the package decision.
Choosing the smallest bag by its printed width can create a weak seal or a stretched package. Measure the finished parcel with the item folded the way it will actually be packed.
Measure the packed item
- Fold the garment or soft product into its shipping shape.
- Measure the widest face and the thickest bulge.
- Check the mailer’s usable interior width and length, including space consumed by seams and flap.
- Test a sample with the exact item mix and seal before ordering a case.
| If the product is… | Start with… |
|---|---|
| Soft apparel or textiles | A non-padded poly mailer with room for folds |
| A garment with a zipper or hard trim | A protective inner sleeve or padded format to prevent punctures |
| A book or rigid flat item | A rigid mailer or small box to protect corners |
| Fragile or crushable | A box and suitable cushioning |
Don’t stretch the mailer to save a size step. Leave enough material for the closure to bond on a clean, flat surface. For the broader packaging choice, compare poly mailers and boxes; include packing time and materials in the cost-per-shipment calculation.
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Common questions
How do I choose a poly mailer size?
Fold the product as it will ship, measure its widest and thickest packed shape, and check the mailer's usable interior dimensions and closure allowance.
Can I use a poly mailer for books?
Use one only when the item is protected from bending and the mailer fits without stress. A rigid mailer or box is often safer for edges and corners.
How much space should I leave for the adhesive flap?
Follow the package dimensions and closure instructions from the mailer manufacturer; the stated size may not include usable interior space at the flap.