Garbage Bag 101

Why Gauge Isn’t Always Important

Film thickness is no longer a satisfactory standard for judging overall strength. The development of improved LLDPE resin in the garbage bag industry has completely changed the standard method for selecting the correct garbage bags. These materials have allowed manufacturers to produce thinner, lighter trash bags which are stronger and more durable than the thicker bags previously made from low density resin. This is why gauge is no longer an effective way to determine garbage bag strength. Instead of stating actual thickness, it is now generally accepted to use terminology such as “Light”, “Medium”, “Heavy”, and “Extra Heavy”.

Each manufacturer has its own blend formulations, so the proportions of these materials vary from one producer to another. The best way to determine the correct garbage bag is to actually test some suggested samples. At W. Ralston, we have our own testing laboratory where we can test our garbage bags or those of another manufacturer and provide you with the test results.


It’s important to know a little bit about what garbage bags are actually made of, and how thicknesses are measured. That way you can determine which of the polyethylene resins and garbage bag gauges will work best for your particular application.


The basic raw material from which garbage bags are made. There are 3 types of resins: Low Density, Linear Low Density and High Density Polyethylene.


Linear Low Density Polyethylene

This resin is highly puncture and tear resistant. These properties make this the best choice for applications where additional strength and stretch are required. Works well for waste with sharp or jagged edges.


High Density Polyethylene

Garbage bags made from this resin are generally available in lower gauges, and are more temperature resistant.


Low Density Polyethylene

An older resin still used mainly in lower end utility garbage bags. It has largely been replaced by Linear Low Density Polyethylene. W. Ralston does not use this resin in any of our garbage bags!


Consumer and Post-Industrial Polyethylene- This is made from recycled post-consumer plastics such as milk jugs and industrial scraps. These are reprocessed and blended with other types of resins to produce new high quality garbage bags.



A term used to describe the thickness of a garbage bag. Low density garbage bags are measured in mils, while High Density garbage bags are generally measured in microns.



Measurement based on one hundred thousandths of an inch (.000). For example, a .55 mil bag would be 55 thousandths of an inch thick. Common low density garbage bags range from .37 to 1.8 mil in thickness.



Based on thousandth of a Millimeter (.000000). High Density garbage bags usually range from 6 to 22 microns in thickness.

Advantages of Linear Low Density Garbage Bags

  1. Maximum puncture and stretch resistance compared to High Density.
  2. Multi-purpose applications.
  3. Most prevalent type of film used in the industry today.
  4. Manufactured in a wide variety of colors.
  5. Compared to traditional low density film, linear low can be run at a lighter gauge with equal strength.

Advantages of High Density Garbage Bags

  1. HMW/HD garbage bags are about 3 times stronger and more durable than ordinary polyethylene garbage bags of the same thickness.
  2. HMW/HD garbage bags require two-thirds less petroleum based raw material to manufacture. Accordingly, they can be made about one-third the thickness of ordinary low density polyethylene garbage bags, so they require only about one-third the ordinary shipping, storage and warehousing cost.
  3. Substantial cost savings per garbage bag.
  4. When they are properly made, HMW/HD garbage bags will rarely “zipper” if punctured.
  5. Extremely wide range of temperature resistance from -40 degrees F to +212 degrees F (boiling).
  6. CFIA, USDA and FDA approved (natural colored garbage bags).

Types of Bag Seals

Flat Bottom Garbage Bags

These bags have a flat bottom and sealed edges on the sides. The bottom remains flat even when the bag is filled, providing stability, and making it easier to stand upright without tipping over.  The design prevents the bag from tipping over, especially when filled with heavy or bulky items and creates a tidy appearance making it easier to organize items within the bag.  Ideal for disposing of heavy or bulky items, organizing recyclables, and maintaining a clean appearance in waste management, the preferred bag seal in the Canadian market.

Side Seal Garbage Bags

These bags are sealed along the sides, creating a seamless construction without a distinct bottom or gussets. They may have a folded or sealed bottom.  Side seal bags are versatile and can be used for various purposes, including general household waste and lightweight items.  The absence of a flat bottom or gussets allows these bags to be stored compactly.  Suitable for everyday household waste, office trash, and light to medium-weight items.

Star Seal Garbage Bags

Star seal bags have a unique star-shaped pattern at the bottom of the bag, created by sealing the bottom in a way that eliminates seams along the edges. This design allows the bag to conform to the shape of the trash can and distribute weight evenly.  The star seal design enhances the strength of the bag, reducing the risk of leaks or tears, even when filled with heavy or sharp items.  Widely used in various settings, including households, offices, restaurants, and commercial establishments, for collecting both wet and dry waste.

While flat bottom, side seal, and star seal garbage bags all serve the purpose of containing waste, they differ in their design, advantages, and common uses. Choosing the right type depends on factors such as the type of waste being disposed of, the desired level of stability and strength, and personal preferences.

Measuring for Correct Garbage Bag Size

Bag Width

Use 1/2 of the outer circumference of the receptacle.

Bag Length

Use the height of the receptacle, plus 1/2 of the container bottom, plus 3 inches (for overhang). For square or rectangular receptacles, use the diagonal of the receptacle bottom rather than the diameter.

Or, go to the calculator here.

Convert Microns to Mils

To convert microns to mils, divide the micron by 25.4 to arrive at the true mil thickness. Or, go to the calculator here.

Convert Mils to Microns

To convert mils to microns, multiply the mil by 25.4 to calculate the true micro thickness. Or, go to the calculator here.

How to Figure Case Weights

Linear Low

Width x Length x Mil /15 = Lbs per 1000 bags.
Calculator here.

High Density

Width x Length x Mic x .0027034 = Lbs per 1000 bags.
Calculator here.