on August 13, 2026

Dog Poop Bag Thickness Explained: Mils, Microns and "2x Thicker"

Let us talk about the moment. You know the moment. You pick up after your dog, you feel warmth through the bag, and your soul briefly leaves your body.

That moment has a unit of measurement. Two, actually, and once you know them the marketing on the box becomes a great deal easier to read.

The unit is a mil, or a micron

Plastic film thickness is quoted in mils in the US and microns almost everywhere else. A mil is not a millimetre, which is the single most common mix up in this category. Per NIST's guide to the SI, a mil is exactly 0.001 inch. Since an inch is exactly 25.4 millimetres, one mil works out at 25.4 microns, or 0.0254 mm.

So a bag advertised at "0.7 mil" and a bag advertised at "18 micron" are the same bag wearing different hats. Here is the conversion so you can compare like for like on a shelf.

Mils to microns, no maths required

Mils Microns Millimetres
0.5 12.7 0.0127
0.7 17.8 0.0178
1.0 25.4 0.0254
1.5 38.1 0.0381
2.0 50.8 0.0508

Calculated from NIST's exact conversion, 1 mil = 0.001 in = 25.4 microns. For context, ASTM defines "film" as sheeting no thicker than 0.25 mm, which is 10 mils, so every bag on the shelf sits at the thin end of that range.

Thickness is a proxy, not the whole answer

Thickness matters because it feeds almost every other property. ASTM D6988, the standard guide for measuring film thickness, exists precisely because thickness is used directly in calculating the results of other tests. Measure the thickness wrong and every strength number downstream is wrong too.

Those downstream tests are the ones that actually describe the three ways a bag betrays you:

  • The puncture. A stick, a claw, one ambitious fingernail. The industry measure closest to this is impact resistance, tested by dropping a weighted dart through the film under ASTM D1709.
  • The tear that travels. A tiny nick near the top opens into a full split halfway home. That is tear propagation, measured by pendulum under ASTM D1922.
  • The stretch failure. The bag holds at pickup, then gives out at the knot or mid swing. That is a tensile property, tested under ASTM D882.

The useful takeaway: a thicker bag is usually a stronger bag, but thickness alone does not guarantee it. Resin blend, how the film was blown, and the quality of the bottom seam all move those numbers independently. A thick bag with a lazy seam still leaks. The seam is where cheap bags quietly give up.

What "2x thicker" does and does not mean

Comparative thickness claims are everywhere, and the trouble is always the missing half of the sentence. Twice as thick as what?

  • It is a comparison, so it needs a baseline. If a brand does not say what it is comparing against, the number is decoration. "2x thicker" against an unnamed competitor is not a specification.
  • Double the thickness is not double the strength. Tear, puncture and tensile performance do not scale in a neat straight line with gauge, which is why they get their own separate test standards.
  • Thickness says nothing about the seam, the length, or the opening. Three of the four things that decide whether the walk home is pleasant.
  • Thicker is not automatically greener. More material per bag, but a bag that fails means two bags used. One good bag beats double bagging a bad one, every time.

Our own numbers, clearly labelled as ours

In the interest of not doing the exact thing we just complained about, here are Waste Happy's own specifications, presented as our claims rather than as independent test results:

  • 50 to 300% thicker than standard bags, depending on which standard bag you put next to it. That is our comparison and our range, stated openly.
  • 14 inches long, so you can tie off with room to spare and your hand never has to work near the payload.
  • Leak proof up to 8.2 lbs, which is considerably more than any single pickup should ever weigh.
  • Easy open, because a thick bag you cannot peel apart while a dog drags you down the street is its own kind of failure.
  • Bio-based, meaning partly plant derived rather than entirely fossil. As the EPA notes, bio-based describes where a plastic came from, not how it breaks down. Our bags are not certified compostable and we do not claim they are.

The one bag rule

Here is the test we build for. You should be able to pick up after a large dog with one bag, zero doubt, and zero awareness of temperature. If you are double bagging, you are paying for two bad bags instead of one good one, which is worse for your wallet and the planet simultaneously.

See the boxes, or take the quiz and we will match you to the right monthly supply.

Sources