The Thick and Thin of Plastic Bags

Whether you’re new to ordering plastic (poly) bags or a seasoned pro, it doesn’t hurt to know more about how the plastic bag industry measures the thickness of plastic bags.

In the United States, the gauge (that is, the thickness) of a poly bag is measured in mils.

What Is a Mil?

A mil is a unit of measurement that is equal to .001”. (This is also referred to as “one one-thousandth of an inch.”) Think of it this way:

1 mil = .001”

… so therefore …

1000 mil = 1” (Not that you’d ever order plastic bags this thick!)

Here’s a quick conversion table that covers the standard ranges of thicknesses:

Mil Thickness Thousandth of an Inch Thickness Best For …
½ mil .0005” Short-term use for lightweight products. A grocery store bag is ½ mil. A dry cleaning bag is ¾ mil.
¾ mil .00075”
1 mil .001” Storing, displaying, and shipping everyday items such as food or clothes. A bread bag is 1.5 mils thick. A trade show bag or retail boutique bag is usually 2 mils.
1.5 mils .0015”
2 mils .002”
3 mils .003” Providing scuff protection and tear resistance during shipping, especially for heavy or abrasive items. Industrial pallet covers are 3 mils.
4 mils .004”
5 mils .005”

Note: Countries outside the U.S. sometimes express the thickness of plastic bags in microns (mic). One mil is equal to 25.4 microns.

How to Choose a Plastic Bag’s Thickness

In the plastic bag industry, it’s crucial to specify the right gauge for the bags you’re ordering. Before specifying a bag’s thickness, think about:

  • The item the bag will contain. Consider the size of the item, as well as its weight. For example, a heavy, medium-sized item would require a thicker gauge than a light, large-sized item.
  • How much protection the bag should provide for the item. If the item is delicate or easily scratched, use a thicker gauge.
  • The length of time the bag will be used. If you want the bag to be reusable, specify a gauge of at least 2 mils (.002”).

If you’ve still got questions about specifying the gauge of your plastic bags, ask us! Drop us an email at or call us tollfree at 1-800-229-9950.

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