Home›Glossary›Mesh Size

Mesh Size

General

Sieve Mesh Size

The number of openings per linear inch in a sieve or screen — a higher mesh number means smaller openings and finer particle separation, an inverse relationship to micron size.

Definition

Mesh Size describes the number of openings per linear inch in a sieve or screen. Counterintuitively, a higher mesh number means smaller openings — a 200-mesh sieve has finer openings than a 20-mesh sieve, since more openings fit into the same linear inch only if each one is smaller.

Because mesh number describes openings per inch while particle size (in microns) describes the actual physical opening dimension, converting between them requires an inverse relationship rather than a simple multiplication. The Mesh-to-Micron Converter applies the standard industry approximation.

Formula

Microns ≈ 15,000 ÷ Mesh Number

Mesh Number ≈ 15,000 ÷ Microns

This is a widely used industry approximation for US Standard mesh, not an exact physical law.

Worked Example

Converting 100 mesh to microns:

Microns = 15,000 ÷ 100 = 150 microns

Converting 44 microns back to mesh:

Mesh = 15,000 ÷ 44 ≈ 341, close to the standard 325-mesh sieve used in fine powder classification.

Key Things to Know

  • Inverse relationship, not proportional: a bigger mesh number means a smaller opening, the opposite of what the number might suggest at first glance.
  • Approximation, not an exact constant: certified sieve manufacturer specifications (ASTM E11, ISO 3310) should be used for regulatory or quality-critical work.
  • Application-dependent range: coarse mesh (4–20) suits aggregates; fine mesh (200–400) suits powders and fine chemicals.
  • US Standard vs Tyler mesh differ slightly: always confirm which numbering system a specification uses before comparing values.

Frequently Asked Questions

Mesh number counts openings per linear inch of screen, so packing more openings into the same inch necessarily makes each individual opening smaller — the relationship is inverse, not proportional.
A 100-mesh sieve corresponds to approximately 150 microns, using the standard industry approximation of microns ≈ 15,000 ÷ mesh. The [Mesh-to-Micron Converter](/mesh-to-micron-converter/) calculates this for any mesh number.
No — it's a widely used industry approximation, not a universal physical constant, since actual sieve opening sizes are defined by standards bodies (ASTM E11, ISO 3310) in certified tables that can deviate slightly, especially at very coarse or fine mesh numbers.
US Standard mesh and Tyler mesh are two different sieve numbering systems that can report slightly different opening sizes for the same nominal mesh number, especially at coarser sizes.
Coarse sieving (4–20 mesh) suits gravel and coarse aggregates, medium sieving (40–100 mesh) suits sand and granular powders, and fine sieving (200–400 mesh) suits pharmaceutical powders and fine chemicals.