Poly mailers are sized by their usable inside dimensions, not the outside. Ordering the wrong size is the most common mistake e-commerce and 3PL buyers make. This guide shows the standard sizes, what fits each, and the specs to confirm before you request a quote.
Mailers are quoted as width x length of the usable inside area, measured below the seal and before the adhesive lip. Always confirm whether a supplier lists inside or outside dimensions, and leave about 1-2 cm of slack around the product so the seal closes flat.
6x9 in (approx 15x23 cm): jewellery, accessories, small apparel. 9x12 in (23x30 cm): t-shirts, single garments, books. 10x13 in (25x33 cm): the e-commerce workhorse for folded apparel. 12x15.5 in (30x40 cm): multiple garments, bedding. 14.5x19 in (37x48 cm) and up: bulky or multi-item orders. Custom sizes are easy at wholesale volume.
Standard co-extruded mailers run about 2.0-2.5 mil (50-65 micron). Go thicker for heavy, sharp or high-value goods. Co-extruded double-layer film is opaque for privacy and far stronger than a single-layer bag of the same gauge - don't spec on thickness alone.
A strong permanent self-seal adhesive is standard; add a second peel-and-seal strip if customers need easy returns. Custom printing (logo, brand colour, care text) is available from low MOQs - send artwork as vector for the cleanest result.
PCR (post-consumer recycled) mailers help meet retailer and EU recycled-content targets. Tell us your destination market so we can match the right recycled percentage and provide the test documentation your buyer needs.
Send the finished inside size, thickness (mil or micron), colour, print (yes/no), monthly volume and destination port. We confirm an exact size match - or measure a sample you send - and quote factory-direct.
Send your sizes, thickness, colour and quantity — we reply with FOB pricing, samples and lead time.