Trash bag thickness is measured in mil (thousandths of an inch) for LLDPE bags and in microns (thousandths of a millimeter) for HDPE bags. 1 mil = 25.4 microns. Light office waste needs only 6–8 micron HDPE or about 0.5–0.7 mil LLDPE, kitchen and food waste 0.7–1.2 mil, heavy commercial loads 1.5–2.0 mil, and contractor debris 2.5–3.0 mil.
The catch: a micron number and a mil number on two boxes do not compare directly, because the two resins behave very differently. A 16 micron HDPE bag (0.63 mil) can carry the same office waste as a 1.5 mil LLDPE bag. This guide explains why, and how to pick the right gauge without paying for plastic you don’t need.
Mil vs micron: the units
- 1 mil = 0.001 inch = 25.4 microns (0.0254 mm). It is a US unit. It has nothing to do with “millimeter”.
- 1 micron (µm) = 0.001 mm = about 0.00004 inch. Outside the US, film is almost always specified in microns.
In the US can liner trade, the convention is simple: low density bags (LLDPE) are labeled in mil, high density bags (HDPE) in microns, sometimes written “mic”. If a box doesn’t say which resin it is, the unit usually tells you.
| Mil | Microns | Microns | Mil | |
|---|---|---|---|---|
| 0.5 | 12.7 | 6 | 0.24 | |
| 0.7 | 17.8 | 8 | 0.31 | |
| 0.9 | 22.9 | 10 | 0.39 | |
| 1.0 | 25.4 | 13 | 0.51 | |
| 1.2 | 30.5 | 16 | 0.63 | |
| 1.5 | 38.1 | 22 | 0.87 | |
| 2.0 | 50.8 | 30 | 1.18 | |
| 3.0 | 76.2 | 50 | 1.97 |
HDPE vs LLDPE: why the numbers don’t compare
Almost all trash bags are polyethylene. The difference is the grade.
HDPE (high density polyethylene)
Stiff, crinkly, a bit translucent. It is strong for its weight and resists pulling, so a very thin film can carry a surprising load. That makes it the cheapest bag per can for paper, office and other dry waste. The weak point: once something pokes a hole in it, the tear runs fast. A broken chair leg or a jagged can lid will split an HDPE bag where an LLDPE bag would just stretch.
LLDPE (linear low density polyethylene)
Soft and stretchy. It gives before it breaks, so it handles wet food waste, glass, sharp edges and heavy, uneven loads much better. It needs more film thickness to carry the same weight, which is why LLDPE bags are sold in mil and look “thicker” on paper.
Many people assume “high density” means stronger. For trash bags that is only half true. HDPE is stronger in tension and per gram of plastic. LLDPE is far better at puncture and tear resistance. Pick the resin for the waste first, then the thickness.
Which thickness for which job
These are the ranges US janitorial and food service buyers order most often. Use them as a starting point, then test with your own waste.
| What goes in the bag | Resin | Thickness |
|---|---|---|
| Office paper, restroom towels, desk-side bins | HDPE | 6–8 µm (0.24–0.31 mil) |
| Mixed office waste, light kitchen waste | HDPE | 10–13 µm (0.39–0.51 mil) |
| Home kitchen bags (13 gal) | LLDPE | 0.7–0.9 mil (18–23 µm) |
| Cafeteria and food waste | HDPE or LLDPE | 13–16 µm, or 0.9–1.2 mil (23–30 µm) |
| Restaurants, wet or heavy loads | LLDPE | 1.2–1.5 mil (30–38 µm) |
| Glass, yard waste, outdoor bins | LLDPE | 1.5–2.0 mil (38–51 µm) |
| Construction debris (contractor bags) | LLDPE | 2.5–3.0 mil (64–76 µm) |
Bag size matters too. A 60-gallon bag full of wet waste weighs far more than a 13-gallon bag, so the same waste type needs a heavier gauge in a bigger bag. Our trash bag size chart lists a typical thickness for each can size.
Thickness is not the whole story
Two bags with the same mil number can perform very differently. From the production floor, these are the things that change strength as much as gauge does.
Resin quality and blend
Bags are blown from molten resin into a tube of film, then flattened, sealed and cut. A bag made from good virgin resin can outperform a thicker bag made with a high share of low-grade recycled material. Recycled content is fine and often required by buyers, but it has to be blended and controlled. When a supplier quotes a much lower price at the same gauge, ask what is in the film.
Seal type
A strong film with a weak bottom seal still fails. Star seal bags have no gussets and spread the load across the bottom, so they leak less and suit heavy loads. Flat bottom seals are fine for small cans. See our star seal bags on roll and C-fold trash bags.
Gauge tolerance
Film thickness is measured with a micrometer at several points across the film, because extruded film is never perfectly even. Ask your supplier what tolerance they work to, and measure samples yourself. A bag sold as 1.25 mil that measures 1.1 mil is 12% less plastic than you paid for.
Equivalent strength claims
Some boxes say “1.5 mil equivalent” or “strength of a 2 mil bag”. That usually means a thinner film made from a stronger resin blend. It can be a good bag, but you can’t check the claim with a ruler. Ask for the actual gauge, and if strength is critical, ask for a dart drop impact result (ASTM D1709).
Black vs white vs clear: does color change strength?
Not by itself. Color comes from a small amount of masterbatch added to the resin. Black film is often used when the bag contains recycled resin, because mixed recycled colors can only be made dark, so some black bags do carry more recycled content. That is a resin question, not a color one. A white or clear bag is not food grade just because of its color. If you need a bag for food contact, that has to be specified and made for it.
Buying tips for importers
- Write the full spec. Resin, thickness with unit, flat size, seal type, color, count per roll. “Heavy duty” on its own means nothing.
- Don’t over-spec. Moving a whole program from 1.5 mil to 1.2 mil cuts film weight by 20%. If the lighter bag holds, that is your saving.
- Use HDPE where you can. For offices, schools and restrooms, HDPE in microns is usually the lowest-cost liner that works.
- Test before you commit. We send free samples in several gauges so you can run them in your own cans with your own waste.
We make HDPE and LLDPE can liners from light office gauges up to heavy duty, in any size, on rolls or flat packed. Plants follow Japan’s JIS standard and ISO 9001. See the range in our trash bag category and our heavy duty trash can liners.
FAQ
Is 1.5 mil thick for a trash bag?
For LLDPE, 1.5 mil is a heavy duty commercial liner. It is right for restaurant waste, heavy wet loads and large cans. For a home kitchen bag it is more than most people need. Contractor bags are thicker, at 2.5–3.0 mil.
How many microns is 1 mil?
25.4 microns. To convert mil to microns, multiply by 25.4. To convert microns to mil, divide by 25.4.
What mil is a good kitchen trash bag?
Most 13-gallon kitchen bags are LLDPE between 0.7 and 0.9 mil. If yours split often, go to about 1.0–1.2 mil, or look at the bottom seal before blaming the thickness.
Why is an HDPE bag rated in microns so much thinner?
HDPE is stiffer and stronger in tension per gram, so it carries light, dry waste at a much lower thickness. A 13–16 micron HDPE liner often replaces a 1.0–1.5 mil LLDPE liner for office waste. It is not a good swap for sharp or wet waste.
Is a thicker trash bag always better?
No. Thicker costs more and uses more plastic. The right bag is the lightest one that holds your waste without splitting. A good resin and a good seal often matter more than an extra 0.2 mil.
Send us the can size, what goes in the bag, and the gauge you use now. We will suggest a resin and thickness and quote it with samples. Get in touch here.