How to choose mailer boxes for online retail: sizing rules, flute types, branding opportunities and cost control.

Mailer boxes are the workhorse of e-commerce packaging. They arrive flat, assemble in seconds, and protect products through the final mile. Choosing the right flute, size and print makes the difference between a damaged package and a five-star unboxing review.

Sizing: measure the product, not the box

Start with your product's outer dimensions, add 10–15mm clearance on each side for bubble wrap or paper fill, then round up to a standard box size. Oversized boxes increase dimensional weight charges, which can add several dollars per shipment. Custom sizes are affordable when you order in volume—see our mailer box range.

Flute types explained

Single-wall E-flute is thin and light, good for lightweight items. B-flute adds cushioning for heavier products. Double-wall BC is for fragile or heavy goods. When in doubt, order a transit test: pack the box with your real product, drop it from 80cm on each edge, and inspect the result.

Branding without blowing the budget

You can start with a plain brown box and a branded tape, then upgrade to single-color flexo printing, and finally full-color mailer boxes with inside print for the unboxing moment. Inside-print is a low-cost way to add a thank-you message and social handles.

Volume and cost

Mailer boxes are priced per square meter of board, so bigger and thicker boxes cost more. Ordering 5,000+ pieces usually unlocks better board pricing and free custom size. Most e-commerce brands keep 2–3 standard sizes in stock and reorder monthly.

Send us your product dimensions for a free sizing recommendation and quote—we reply within 24 hours.