Mesh to Micron Converter
Mesh to micron: a No. 200 US sieve has a 75 µm opening, No. 100 is 150 µm and No. 325 is 45 µm (ASTM E11). Higher mesh numbers mean finer openings.
No. 200 mesh = 75 µm = 0.075 mm = 0.002953 in
Mesh to Micron Sieve Chart (ASTM E11)
| US sieve No. (mesh) | Opening (µm) | Opening (mm) | Opening (in) |
|---|---|---|---|
| No. 3½ | 5600 | 5.6 | 0.22 |
| No. 4 | 4750 | 4.75 | 0.187 |
| No. 5 | 4000 | 4 | 0.157 |
| No. 6 | 3350 | 3.35 | 0.132 |
| No. 7 | 2800 | 2.8 | 0.11 |
| No. 8 | 2360 | 2.36 | 0.0929 |
| No. 10 | 2000 | 2 | 0.0787 |
| No. 12 | 1700 | 1.7 | 0.0669 |
| No. 14 | 1400 | 1.4 | 0.0551 |
| No. 16 | 1180 | 1.18 | 0.0465 |
| No. 18 | 1000 | 1 | 0.0394 |
| No. 20 | 850 | 0.85 | 0.0335 |
| No. 25 | 710 | 0.71 | 0.028 |
| No. 30 | 600 | 0.6 | 0.0236 |
| No. 35 | 500 | 0.5 | 0.0197 |
| No. 40 | 425 | 0.425 | 0.0167 |
| No. 45 | 355 | 0.355 | 0.014 |
| No. 50 | 300 | 0.3 | 0.0118 |
| No. 60 | 250 | 0.25 | 0.00984 |
| No. 70 | 212 | 0.212 | 0.00835 |
| No. 80 | 180 | 0.18 | 0.00709 |
| No. 100 | 150 | 0.15 | 0.00591 |
| No. 120 | 125 | 0.125 | 0.00492 |
| No. 140 | 106 | 0.106 | 0.00417 |
| No. 170 | 90 | 0.09 | 0.00354 |
| No. 200 | 75 | 0.075 | 0.00295 |
| No. 230 | 63 | 0.063 | 0.00248 |
| No. 270 | 53 | 0.053 | 0.00209 |
| No. 325 | 45 | 0.045 | 0.00177 |
| No. 400 | 38 | 0.038 | 0.0015 |
| No. 450 | 32 | 0.032 | 0.00126 |
| No. 500 | 25 | 0.025 | 0.000984 |
| No. 635 | 20 | 0.02 | 0.000787 |
Nominal openings from ASTM E11 (standard designation in mm/µm, alternative designation No.). Inch values are converted and rounded.
Reference
ASTM International. (2024). Standard specification for woven wire test sieve cloth and test sieves (ASTM E11-24). https://store.astm.org/e0011-24.html
Frequently asked questions
How many microns is 200 mesh?
A No. 200 sieve has a 75 µm opening (ASTM E11), so particles that pass 200 mesh are finer than about 75 µm.
How many microns is 100 mesh?
150 µm. Other common sizes: 60 mesh = 250 µm, 325 mesh = 45 µm, 400 mesh = 38 µm.
What does mesh number mean?
Originally the number of wires per inch of sieve cloth. Because wire thickness varies, the opening is not simply 25.4 mm ÷ mesh; standard sieves are defined by their nominal opening, and the mesh number is the alternative designation.
Does a higher mesh number mean a finer sieve?
Yes. More wires per inch means smaller openings: No. 20 is 850 µm, No. 200 is 75 µm.
Are ASTM E11 and ISO 3310-1 sieves the same size?
The openings in micrometres follow the same ISO 565 R 40/3 series, so a 75 µm sieve is 75 µm in both. ASTM adds the US sieve numbers; ISO uses the opening only.
Sources
- ASTM E11 Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves, ASTM International .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
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APA
Scientific Converters. (2026, October 15). Mesh to Micron Converter. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/mesh-to-micron/
IEEE
Scientific Converters, "Mesh to Micron Converter," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/mesh-to-micron/