Plastic Bag Gauge Explanation

What does gauge mean when describing a polythene bag?

One answer is "absolutely nothing" to many suppliers as the level of under-declaring the gauge of plastic bags has got to rediculous proportions. When we purchase from third parties (when tempted by the price being lower than our own), we find that what is specified at 500 gauge comes out at 400 gauge. This makes it impossible to compare different suppliers as those which under-declare the most will always win on price.

Some suppliers overcome this by not specify the gauge and giving product names or even descriptions such as "extra heavy" which prevents comparison.

We see rubble sacks described as "Super strong black rubble sack for disposing of building waste" which are also declared as 80um (320 gauge). Our lightest-weight rubble sack is 400 gauge!

We are breaking this trend by offering actual gauge - the only way to tell is to purchase a stocked product for comparison with your usual supplier. Although we still do have to have a manufacturing tolerance we don't start by taking 20% off (or anything off) and go to great lengths to maintain our quality. Our customers find this to be a refreshing change as you can actually compare products even within our own range and ensures that we keep customers long-term.

Technically, gauge is the measurement of thickness of standard low density plastic bags. It is related to the SI measurement of microns as 1 micron is approximately 4 gauge. Typical gauge sizes and microns equivalent are:

  • 100 gauge = 25 microns = 0.025mm = Very light-weight, economy black bin liner typically sold in discount stores.
  • 120 gauge = 30 microns = 0.03mm = Standard bin liner.
  • 160 gauge = 40 microns = 0.04mm = General purpose, quality black bin liner for domestic kitchen waste.
  • 200 gauge = 50 microns = 0.05mm = Heavy duty black bin liner - suitable for commercial kitchen waste.
  • 300 gauge = 75 microns = 0.075mm = Heavy duty garden waste bag.
  • 400 gauge = 100 microns = 0.1mm = Typical rubble sack when gauge is not specified.
  • 500 gauge = 125 microns = 0.125mm = Tough rubble sack - suitable for up to 40kg load.

Regardless of the thickness, sharp objects will puncture polythene (glass and metal). Thin bags will tear by pure weight or once punctured, however the thicker the bags will not tear easily without first being punctured.

Some bags are made from medium or high density polythene. This makes them more crinckly (like a supermarket carrier bags) and can be made thinner for the same strength. The thickness in microns is used to describe these bags:

  • 4 microns = the thinnest paper wate bin liner we have ever seen (hardly stronger than a tea bag!)
  • 6 microns = thin bin liner used in hotels


We recommend that you purchase our stocked products to try (even if the requirement is for special size or thickness). For our policy on samples, please see:

https://www.plasticbagsuppliers.co.uk/samples.html