Usually the fineness of the powder is expressed by "mesh", which is defined as the number of meshes in an area of 1 square inch, that is, the number of meshes in the sieve, and the number of meshes that the powder mesh number. The larger the mesh number, the smaller the particle size. Talc powder is usually divided into 400 mesh, 800 mesh, 1000 mesh, and 1250 mesh superfine talc powder according to the grade. Table 2 can be used to convert powder particle size mesh to micron.
Mesh and micron conversion table
| Mesh | Micron | Mesh | Micron | |
| 20 | 850 | 270 | 53 | |
| 25 | 710 | 325 | 45 | |
| 30 | 600 | 400 | 38 | |
| 35 | 500 | 450 | 32 | |
| 40 | 425 | 500 | 28 | |
| 45 | 355 | 600 | twenty three | |
| 50 | 300 | 700 | 20 | |
| 60 | 250 | 800 | 18 | |
| 70 | 212 | 1000 | 13 | |
| 80 | 180 | 1250 | 10 | |
| 100 | 150 | 1670 | 805 | |
| 120 | 125 | 2000 | 605 | |
| 140 | 106 | 5000 | 205 | |
| 170 | 90 | 8000 | 105 | |
| 200 | 75 | 10000 | 1.3 | |
| 230 | 63 | 12000 | 1.0 |
