Sep 9, 2026Technical Notes
Mesh Count, Micron Rating and Opening Size: What They Mean
A plain-language explanation of how wire mesh is measured, and why micron rating matters more than mesh count for filtration.
Mesh count explained
Mesh count is the number of openings per linear inch, written like 100x100 for square mesh. It describes how fine the cloth is, but not the exact opening size.
In dutch weave, the count is written as warp x shute, for example PDW 24x110 or TDW 165x800.
Why micron rating matters
Opening size in micron (one thousandth of a millimetre) is what determines which particles pass through. Two cloths with the same mesh count can differ in opening if the wire diameter differs.
EPFilter's square woven mesh opens from about 20 micron at 635 mesh to about 7000 micron at 2 mesh.
Plain dutch and twilled dutch ratings
Dutch weaves use shaped openings that retain particles on the surface and build filter cake. Ratings are given as absolute and nominal micron values.
For example PDW 8x20 has an absolute rating near 330-350 micron; fine TDW 400x2800 reaches absolute ratings of about 6-7 micron.
Open area and flow
Open area is the percentage of the cloth that is hole. Higher open area means less flow resistance and often easier cleaning.
Where drainage or airflow matters, choose a weave with higher open area for the required retention.
Choosing a rating
Decide the particle size you must stop, then select a mesh whose absolute rating is finer than that particle.
If you are unsure of the right count, send EPFilter your application and target micron, and we will recommend a weave.