In China, mesh count is typically expressed by the number of mesh holes per centimeter, while internationally, it is commonly measured by the number of mesh holes per inch. Additionally, there is a method of expressing it by the size of each mesh hole (unit: mm). A larger mesh count indicates finer particle size; conversely, a smaller mesh count means coarser particle size. Screening particle size, i.e., the size of particles that can pass through a sieve mesh, is defined by the number of mesh holes in an area of 1 square inch (25.4mm×25.4mm), which is the so-called mesh count. It is worth noting that the specifications of standard sieves may vary from country to country, but the commonly used Tyler system uses the number of holes per inch as the sieve number, called mesh. For example, a 100-mesh sieve means there are 100 mesh holes per inch of the sieve.
The correspondence between mesh hole size and standard mesh count is as follows:
| Mesh Count | Aperture (mm) | Mesh Count | Aperture (mm) | Mesh Count | Aperture (mm) |
|---|
| 2 mesh | 12.5 | 45 mesh | 0.4 | 220 mesh | 0.065 |
| 3 mesh | 8 | 50 mesh | 0.355 | 240 mesh | 0.063 |
| 4 mesh | 6 | 55 mesh | 0.315 | 250 mesh | 0.061 |
| 5 mesh | 5 | 60 mesh | 0.28 | 280 mesh | 0.055 |
| 6 mesh | 4 | 65 mesh | 0.25 | 300 mesh | 0.050 |
| 8 mesh | 3 | 70 mesh | 0.224 | 320 mesh | 0.045 |
| 10 mesh | 2 | 75 mesh | 0.2 | 325 mesh | 0.043 |
| 12 mesh | 1.6 | 80 mesh | 0.18 | 340 mesh | 0.041 |
| 14 mesh | 1.43 | 90 mesh | 0.16 | 360 mesh | 0.040 |
| 16 mesh | 1.25 | 100 mesh | 0.154 | 400 mesh | 0.0385 |
| 18 mesh | 1 | 110 mesh | 0.15 | 500 mesh | 0.0308 |
| 20 mesh | 0.9 | 120 mesh | 0.125 | 600 mesh | 0.026 |
| 24 mesh | 0.8 | 130 mesh | 0.112 | 800 mesh | 0.022 |
| 26 mesh | 0.71 | 140 mesh | 0.105 | 900 mesh | 0.020 |
| 28 mesh | 0.68 | 150 mesh | 0.100 | 1000 mesh | 0.015 |
| 30 mesh | 0.6 | 160 mesh | 0.096 | 1800 mesh | 0.010 |
| 32 mesh | 0.58 | 180 mesh | 0.09 | 2000 mesh | 0.008 |
| 35 mesh | 0.50 | 190 mesh | 0.08 | 2300 mesh | 0.005 |
Correspondence between specific aperture sizes and standard mesh counts:
Sieve aperture 2.00mm corresponds to 10 mesh.
Sieve aperture 1.70mm corresponds to 12 mesh.
Sieve aperture 1.40mm corresponds to 14 mesh.
Sieve aperture 1.18mm corresponds to 16 mesh.
Sieve aperture 1.00mm corresponds to 18 mesh.
Sieve aperture 0.850mm corresponds to 20 mesh.
Sieve aperture 0.710mm corresponds to 25 mesh.
Sieve aperture 0.600mm corresponds to 30 mesh.
Sieve aperture 0.500mm corresponds to 35 mesh.
Sieve aperture 0.425mm corresponds to 40 mesh.
Sieve aperture 0.355mm corresponds to 45 mesh.
Sieve aperture 0.300mm corresponds to 50 mesh.
Sieve aperture 0.250mm corresponds to 60 mesh.
Sieve aperture 0.212mm corresponds to 70 mesh.
Sieve aperture 0.180mm corresponds to 80 mesh.
Sieve aperture 0.150mm corresponds to 100 mesh.
Sieve aperture 0.125mm corresponds to 120 mesh.
Sieve aperture 0.106mm corresponds to 140 mesh.
Sieve aperture 0.090mm corresponds to 170 mesh.
Sieve aperture 0.075mm corresponds to 200 mesh.
Sieve aperture 0.063mm corresponds to 230 mesh.
Sieve aperture 0.053mm corresponds to 270 mesh.
Sieve aperture 0.045mm corresponds to 325 mesh.
Sieve aperture 0.040mm corresponds to 400 mesh.
Sieve aperture 0.013mm corresponds to 500 mesh.
Note: When a positive or negative sign is added before a number, it indicates whether particles can pass through the mesh. A negative sign means particles can pass through the mesh (i.e., their size is smaller than the mesh hole), while a positive sign means particles cannot pass through (i.e., their size is larger than the mesh hole). For example, particles of -100~+200 mesh can pass through a 100-mesh sieve but cannot pass through a 200-mesh sieve. When screening such particles, the larger sieve (200 mesh) should be placed below the smaller sieve (100 mesh) to ensure that only -100~+200 mesh particles remain on the 200-mesh sieve.
