How to Specify Side Gusset Bags: Width, Gusset, Length and Thickness

Side gusset bags add expandable depth without changing the front face in the same way as a wider flat bag. They are used for carton liners, industrial parts, food ingredients, garments and bulky products. The most common quotation error is an unclear dimension format, so this guide starts with measurement.

How to write side gusset bag dimensions

A specification may be written as face width x gusset depth x length, but suppliers do not always use the same convention. Some state the total gusset depth; others state the fold on each side. For example, a 100 mm total gusset may mean two 50 mm folds. The safest RFQ includes a simple drawing showing:

• Front face width
• Total finished length
• Gusset depth and whether it is total or per side
• Open end and seal location
• Any perforation, handle, vent hole or special seal

State thickness per side

Always mark thickness as single-side thickness. A closed bag has two film walls, so total thickness measured across both walls is roughly double the single film gauge. HengYi's general PE processing capability is approximately 0.008-0.20 mm single-side thickness, but the recommended gauge depends on size, gusset depth, load, sharp edges and resin.

For a heavy carton liner, a load test or filled sample is more useful than choosing thickness from a catalog alone. The gusset creates additional stress at folds and seals, especially when the contents press into corners.

Size capability and structure options

General PE film and bag production can cover widths from about 7 cm up to 2 m, subject to structure and equipment layout. Very long flat bags can also be made with manual bag-making methods when appropriate. Side gussets, perforation, roll perforation, heat sealing, open-top construction and handle punching are available after drawing review.

MOQ changes with bag area and printing

A small bag uses less resin per piece and therefore needs a higher piece count to reach an efficient production run. A larger, thicker gusset bag may reach the required material volume with fewer pieces. Printing adds plate and setup costs. As a practical reference near 0.04 mm single-side thickness, a 20 x 30 cm printed bag may start around 20,000 pieces, while a 40 x 50 cm printed bag may start around 10,000 pieces. Unprinted quantities may be about half. Final MOQ must be recalculated for the actual gusset and film area.

Quality checkpoints for gusset bags

• Incoming resin and additive verification
• Film width and single-side thickness inspection
• Gusset fold position and symmetry
• Finished length and seal position
• Seal-strength and load checks
• Outgoing sampling before packing

Normal production targets are around +/-3% for thickness and around +/-1 mm for dimensions where the structure allows. Actual order quantity may vary within 5%, with the balance adjusted to the delivered quantity.

Quotation checklist

Send a dimension drawing, single-side thickness, packed product and weight, material/color, printing file, quantity, packing method and destination. See our custom PE side gusset bags for a product reference.