How to Specify Box Bags for Heavy or Rigid Contents
Box bags solve the problem flat totes cannot: keeping rigid, upright contents stable in transit. The square bottom spreads carried weight across the full base, so cake boxes, food containers, and cartons sit flat and arrive undamaged. Fabric weight, seam construction, and closure are the three decisions that matter.
Where the Load Capacity Comes From
A box bag's load capacity is set at the base. Dense fabric in the 120–150 gsm range combined with a defined square bottom spreads downward pressure evenly instead of concentrating it on one seam line. This is what prevents handle tear-out and bottom seam failure under loads like books, wine bottles, and bulk grocery orders — failure modes that flat bags hit far sooner.
Fabric Weight Against Shape and Load
Bulk orders are usually quoted across these bands:
| Fabric Weight | Characteristics | Recommended Use |
| 80–100 gsm | Cost-effective baseline; stands on its own | Standard retail checkout, light promotional packaging |
| 120 gsm | Balanced rigidity and load capacity | Food delivery, premium apparel packaging |
| 150 gsm | Maximum stiffness, close to cardboard feel | Luxury gifting, multi-bottle beverage transport |
Seams and Closures
Ultrasonic sealing gives clean edges and consistent quality at high volume, and covers most retail and delivery loads. At the top of the weight range, stitched seams with reinforced handles are the safer specification — the weld becomes the weak point before the fabric does. Food transport orders should add a zipper or Velcro closure: it secures contents in transit and, on insulated versions, meaningfully extends temperature retention by limiting air exchange.
