Poly Bubble Mailer Size Guide: Which Size for Which Product?

Choosing the right poly bubble mailer size both ensures the product arrives safely and optimizes your shipping cost. Too large an envelope raises the volumetric-weight charge and lets the product shift inside; too small an envelope squeezes the product and strains the flap. In this guide we detail our 7 standard sizes and which one suits which product.

Small Sizes (10–18 cm)

• 10x15+5 cm: Jewelry, USB drives, memory cards, small electronics, cosmetic samples
• 15x20+5 cm: Phone cases, cosmetic items, jewelry boxes, small fragile items
• 18x23+5 cm: Books, cosmetic sets, electronic accessories, small gift items

Medium Sizes (25–30 cm)

• 25x30+5 cm: Tablets, glass/ceramic items, small textiles, medium-sized fragile items
• 30x37+5 cm: Book sets, electronics boxes, gift packs, medium-to-large fragile items

Large Sizes (35–40 cm)

• 35x45+5 cm: Apparel, shoe boxes, medium-sized fragile items, multi-item shipments
• 40x50+5 cm: Large fragile products, multi-item packs, bulky gifts

What Does "+5" Mean?

The "+5" in the size designation refers to the flap allowance at the top of the envelope (the part where the self-adhesive tape is). In other words, the usable inner dimension of a 35x45+5 cm envelope is 35x45 cm; there is an extra 5 cm of adhesive tape/flap area at the top.

The Right Size Selection Rule

Choose a size that leaves 1–2 cm of space around the product once it is laid flat. Envelopes that are too tight compress the bubble cushioning too much and are hard to seal; in envelopes that are too loose, the product shifts in transit and can take a hit. When in doubt, go one size up.

Mixed-Stock Tip

For sellers who sell across multiple categories, keeping 3 different sizes in stock is ideal: small (15x20), medium (25x30) and large (35x45). These three sizes cover most fragile-product needs. You can see all sizes and prices on our site.