Gusseted Poly Bags: Types, How to Measure, Sizes and Uses

A gusseted poly bag is a polyethylene bag with folded-in pleats (gussets) on the sides or bottom that open out when the bag is filled. The gussets turn a flat bag into a box shape, so it holds bulky or square items, stands up better and packs neatly into cartons. Sizes are written as width x gusset x length, for example 12 x 8 x 24 in.

Below we cover the gusset types, how to measure them without getting the wrong bag, which film to choose, and where gusseted bags are used.

Types of gusseted poly bags

Side gusset bags

The two sides are folded inward along the length of the bag. Filled, the bag opens into a rectangular box shape. This is the classic gusseted poly bag, used for bread, coffee, clothing, bedding, parts and bulk goods. Grocery T-shirt bags are side-gusseted too; the handles are punched out of the top of the gussets. So are pallet covers, which are simply very large side-gusseted bags made to drop over a pallet load.

Bottom gusset bags

The fold is in the base, so the bag stands up on its own when filled. Common for stand-up food bags, gift bags and retail bags that sit on a shelf.

Block bottom (square bottom) bags

The gusseted end is folded and sealed flat, giving a rectangular base like a paper grocery sack. These stand up well and look tidy on display, at a higher price than a simple side-gusset bag.

How to measure a gusseted bag

This is where most ordering mistakes happen, because suppliers do not all list dimensions in the same order.

• Width: across the face of the bag, from fold to fold, with the gussets tucked in.
• Gusset (depth): the full width of the gusset when it is opened out. A 4 in gusset is two 2 in folds, one on each side of the center line.
• Length: from the open mouth to the bottom seal.

So a 12 x 8 x 24 in bag is 12 in wide, has an 8 in gusset and is 24 in long. Watch out: some catalogs list width x depth x height, and some suppliers add the gusset to the width and give a single “flat width”. Always confirm the order of numbers, and send a drawing or a sample bag if you can. US distributors allow tolerance on size and gauge, typically around plus or minus a quarter inch on size and 10% on thickness, so tell us if you need tighter.

Common stock sizes

Size (W x G x L)	Metric (approx.)	Typical gauge	Typical use
8 x 4 x 18 in	20 x 10 x 46 cm	1–2 mil (25–51 µm)	Bread, small parts, coffee
12 x 8 x 24 in	30 x 20 x 61 cm	1.5 mil (38 µm)	Clothing, linens, medium parts
12 x 8 x 30 in	30 x 20 x 76 cm	2 mil (51 µm)	Taller items, garment packs
18 x 14 x 36 in	46 x 36 x 91 cm	2 mil (51 µm)	Bedding, pillows, carton liners
20 x 18 x 36 in	51 x 46 x 91 cm	2–3 mil (51–76 µm)	Box liners, bulk goods
44 x 36 x 80 in	112 x 91 x 203 cm	2 mil (51 µm)	Gaylord liners, pallet and machine covers

These are sizes that US packaging distributors keep in stock. We make gusseted bags to custom size, so you can order exactly what fits your product or carton.

Which film to choose

Gusseted bags are not only HDPE. They are made from several films, and the choice changes how the bag behaves:

Film	Feel and look	Strengths	Weak spots
LDPE / LLDPE	Soft, clear to slightly hazy	Stretches before tearing, good puncture resistance, seals well	Thicker gauge needed for the same strength as HDPE
HDPE	Crisp, rustly, translucent	Strong for its weight, cheaper per bag, good moisture barrier	Tears and punctures on sharp edges
PP / OPP	Glass-clear, stiff	Best clarity for retail display	Brittle in cold, poor tear resistance once nicked

For clothing and bedding, LDPE is the usual choice because it does not split when a corner catches. For bread and bakery, both LDPE and HDPE are used. For crystal-clear display bags, look at PP and OPP bags. Bags that hold food can be made from FDA-compliant food-contact material (21 CFR 177.1520).

Where gusseted poly bags are used

Food packaging

Bread and bakery, coffee beans, rice and grains, frozen vegetables and snacks. The gusset gives a square pack that fills a shelf neatly and holds more product than a flat bag of the same face size. Wicket-packed gusseted bags speed up hand loading on bakery lines.

Apparel, bedding and home textiles

Folded garments, comforters, pillows and towels need depth, not just width. A gusseted bag keeps the fold sharp and protects against dust and moisture in the warehouse.

Industrial and carton liners

Large gusseted bags line corrugated boxes and Gaylord containers, keeping powders, resin, parts and food ingredients clean and dry. The same shape scaled up becomes a pallet cover.

Retail and promotional bags

Side-gusseted bags with a printed face carry branding well. If you want your logo on them, we print up to 8 colors by gravure. See custom printing.

Storage and moving

Gusseted bags hold bulky household items for storage, keeping out dust and damp.

A note on recycling

Polyethylene bags are recyclable, but not through most US curbside bins. Most curbside programs do not accept plastic bags or film, because film wraps around sorting equipment. Clean, dry PE bags are usually taken at store drop-off bins instead. If you print recycling wording on the bag, make sure it matches the rules in the market where it will be sold.

What to send us when ordering

• Width x gusset x length, and which convention you are using.
• Film (LDPE, HDPE, PP) and thickness in mil or microns.
• Side gusset, bottom gusset or block bottom.
• Clear, white or colored film; print colors and sides if printed.
• Extras: wicket packing, zipper, header, perforation on a roll, vent holes.
• Food contact or not, and target market.
• Your carton design, barcode labels and shipping marks if you need them.

FAQ

What is the difference between a gusseted bag and a flat bag?

A flat poly bag has two layers of film sealed on three sides and no depth. A gusseted bag has folded sides or a folded bottom that open out, so it holds square or bulky items and can stand up when filled.

How do you measure the gusset on a poly bag?

Open the side fold out fully and measure across it. A bag with 2 in folds on each side of the center line has a 4 in gusset. List the size as width x gusset x length and confirm the order with your supplier.

Are gusseted poly bags food safe?

They can be. Ask for FDA-compliant food-contact material (21 CFR 177.1520) and keep printing on the outside face of the bag.

Are gusseted bags more expensive than flat bags?

Slightly, because the gusset adds film and a folding step. For bulky products you often save it back, because a smaller face size with a gusset holds the same volume as a much bigger flat bag.

Can gusseted poly bags be printed?

Yes. The front and back faces print like any other bag. Keep key artwork away from the gusset folds, where the print will crease.

If you buy gusseted bags for food, apparel or industrial packing, send us your size, film and quantity. A sample bag or a photo of your current bag with a tape measure helps. We will send free stock samples and a quote on FOB, CFR or CIF terms.