Magnified schematic — the wire-to-opening ratio is true to scale; very thin lines are drawn at a minimum visible width.
A US standard No. 200 test sieve (ASTM E11) has a nominal opening of 75 µm.
| Opening (microns) | 75 µm |
| Opening (millimeters) | 0.075 mm |
| Opening (inches) | 0.003 in |
| US standard sieve | No. 200 |
| Tyler equivalent | 200 mesh |
| Pitch (wire center to center) | 125 µm |
| Typical wire diameter | 0.05 mm |
| Approx. open area | 36% |
A 75 µm opening falls within the very fine sand (62.5 µm–125 µm) class of the Wentworth grain-size scale. Comparing grain size with the nominal opening only: silt and finer would pass; fine sand and coarser would be retained; very fine sand is split at about 75 µm. Real sieving also depends on particle shape, sieving time and the opening tolerance of the cloth.
These applications commonly use a 200 mesh count or an opening near 75 µm:
24, 50, 80, 100 or 200 mesh
Agricultural nozzle tip strainers are offered with stainless screens of 24, 50, 80, 100 or 200 mesh to keep spray tips from plugging.
No. 4 (gravel/sand) · No. 200 (fines)
ASTM D2487 uses the No. 4 sieve (4.75 mm) to separate gravel from sand and the No. 200 sieve (75 µm) to define fines.
100 µm in-tank strainer; 70–100 µm pre-pump
In-tank stainless strainers rated 100 µm protect the pump from debris; guidance for pre-pump filtration on carbureted systems is about 70–100 µm. Injector protection needs a finer post-pump filter.
Ranges show common practice with sources on the mesh size by application page — always check your equipment maker's recommendation.
The name "200 mesh" suggests 200 openings per inch, i.e. a pitch of 25,400 ÷ 200 = 127 µm. Standard test sieves, however, are defined by their opening, not by the count: a 75 µm opening woven with the typical 0.05 mm wire gives a real pitch of 75 + 50 = 125 µm, which is about 203.2 wires per inch. That is why mesh numbers and micron values never line up perfectly — and why this site uses the ASTM E11 opening as the answer.
| Mesh | Microns (µm) | Millimeters | Inches |
|---|---|---|---|
| 140 mesh | 106 | 0.106 | 0.0042 |
| 150 mesh | 106 | 0.106 | 0.0042 |
| 170 mesh | 90 | 0.09 | 0.0035 |
| 200 mesh | 75 | 0.075 | 0.003 |
| 230 mesh | 63 | 0.063 | 0.0025 |
| 250 mesh | 63 | 0.063 | 0.0025 |
| 270 mesh | 53 | 0.053 | 0.0021 |
Values are ASTM E11 nominal openings (Tyler equivalents for 150 and 250 mesh). Italic ≈ values are estimates for non-standard mesh counts, calculated from the mesh count and an assumed wire diameter (interpolated between ASTM E11 sieves, or extrapolated beyond No. 635). Wire values are ASTM E11 typical wire for standard sizes.
200 mesh is 75 µm, which is 0.075 mm or 0.003 inches.
In a simplified comparison with the nominal opening, particles smaller than about 75 µm can pass a 200 mesh screen. A 75 µm opening falls within the very fine sand (62.5 µm–125 µm) class of the Wentworth grain-size scale. Comparing grain size with the nominal opening only: silt and finer would pass; fine sand and coarser would be retained; very fine sand is split at about 75 µm. Real sieving also depends on particle shape, sieving time and the opening tolerance of the cloth.
With a typical 0.05 mm wire, 200 mesh has roughly 36% open area. Thicker wire lowers the open area and the opening size.