Poly bag thickness — when 1.5 mil is enough and when you need 4.

What "mil" actually measures

One mil = one one-thousandth of an inch (0.001"). A 1.0 mil bag is half as thick as a 2.0 mil bag. The thickness affects:

• Puncture resistance — higher mil resists sharp edges and corners.
• Tear strength — higher mil resists tear propagation.
• Stretch — lower mil stretches more under load.
• Cost — material cost scales roughly linearly with mil.

Thickness by use case

0.5 – 1.0 mil — light retail and produce

Wicketed produce bags, light garment bags, retail point-of-sale bags. Use only for soft, light items with no sharp edges.

1.0 – 1.5 mil — light shipping

General light retail and e-commerce. Apparel, soft goods, light accessories.

1.5 – 2.0 mil — standard shipping

Most general-purpose shipping bags for products without sharp edges. Auto parts (smooth), small electronics in inner packaging, dry goods.

2.0 – 3.0 mil — moderate-weight shipping

Heavier products, items with mild edges, moderate stacking. Common for hardware, fasteners, food packaging.

3.0 – 4.0 mil — heavy goods and industrial

Heavy parts, palletized small items, mattress overwrap, products with sharp corners.

4.0 – 6.0 mil — premium protection and large items

Furniture overwrap, mattress bags, large industrial parts, applications with stacking pressure or rough handling.

When higher isn't better

Common over-spec scenarios where 4 mil is bought but 2 mil would have worked:

• Smooth-edged products under 5 lb being palletized — 2 mil is fine.
• Apparel and soft goods — 1.5 mil is usually plenty.
• Small electronics in their own box — the bag just needs to be a dust barrier, 1.5–2 mil is fine.

Material matters as much as thickness

A 2 mil LLDPE bag is roughly as strong as a 3 mil LDPE bag in puncture resistance.

• LDPE — flexible, low cost, lower strength per mil.
• LLDPE — better puncture and tear at lower mil. Default for industrial.
• HDPE — stiffer, higher strength, lower clarity.
• MDPE — middle ground.
• Anti-static (pink LDPE) — for electronics; thickness as needed for handling.

If you're choosing between higher LDPE mil and lower LLDPE mil, LLDPE almost always wins on cost per unit of strength.

A practical specification approach

1. Product weight — under 5 lb (light), 5–25 lb (medium), 25+ lb (heavy).
2. Edge sharpness — smooth (no upgrade), moderate (1 mil up), sharp (2 mil up).
3. Handling environment — gentle (no upgrade), parcel/LTL (1 mil up), bulk truck or hand-tossed (2 mil up).
4. Sum the upgrades against your starting mil for the weight class.

Example: a 12 lb metal fitting going LTL. Start at 2 mil (medium weight). +2 for sharp edges. +1 for LTL handling. Spec at 5 mil — or step to LLDPE at 3 mil to save cost.