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. 100 test sieve (ASTM E11) has a nominal opening of 150 µm.
| Opening (microns) | 150 µm |
| Opening (millimeters) | 0.15 mm |
| Opening (inches) | 0.0059 in |
| US standard sieve | No. 100 |
| Tyler equivalent | 100 mesh |
| Pitch (wire center to center) | 250 µm |
| Typical wire diameter | 0.1 mm |
| Approx. open area | 36% |
A 150 µm opening falls within the fine sand (125 µm–250 µm) class of the Wentworth grain-size scale. Comparing grain size with the nominal opening only: very fine sand and finer would pass; medium sand and coarser would be retained; fine sand is split at about 150 µm. Real sieving also depends on particle shape, sieving time and the opening tolerance of the cloth.
These applications commonly use a 100 mesh count or an opening near 150 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.
60 mesh latex · 100 mesh stain/lacquer
Use 60 mesh for primer and latex paint, 100 mesh for thinner materials such as stain and lacquer.
100 mesh (≈ 150 µm); 60 mesh (≈ 240 µm) suggested
Pump inlet strainers are commonly 100 mesh (≈ 150 µm); one engineering recommendation is 60 mesh (≈ 240 µm) where a suction strainer is used, to lower cavitation risk.
60 mesh (254 µm) · 100 (152 µm) · 140 (104 µm)
Replacement screens are offered at 60 mesh (254 µm) and finer options such as 100 mesh (152 µm) and 140 mesh (104 µm); pick the coarsest screen that catches your sediment, since finer screens clog faster.
No. 4, 8, 16, 30, 50, 100 sieves
ASTM C33/C33M-23 grades fine aggregate on the No. 4 to No. 100 sieves: 95–100% passing No. 4 (4.75 mm) and 0–10% passing No. 100 (150 µm).
Ranges show common practice with sources on the mesh size by application page — always check your equipment maker's recommendation.
The name "100 mesh" suggests 100 openings per inch, i.e. a pitch of 25,400 ÷ 100 = 254 µm. Standard test sieves, however, are defined by their opening, not by the count: a 150 µm opening woven with the typical 0.1 mm wire gives a real pitch of 150 + 100 = 250 µm, which is about 101.6 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 |
|---|---|---|---|
| 60 mesh | 250 | 0.25 | 0.0098 |
| 70 mesh | 212 | 0.212 | 0.0083 |
| 80 mesh | 180 | 0.18 | 0.0071 |
| 100 mesh | 150 | 0.15 | 0.0059 |
| 120 mesh | 125 | 0.125 | 0.0049 |
| 140 mesh | 106 | 0.106 | 0.0042 |
| 150 mesh | 106 | 0.106 | 0.0042 |
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.
100 mesh is 150 µm, which is 0.15 mm or 0.0059 inches.
In a simplified comparison with the nominal opening, particles smaller than about 150 µm can pass a 100 mesh screen. A 150 µm opening falls within the fine sand (125 µm–250 µm) class of the Wentworth grain-size scale. Comparing grain size with the nominal opening only: very fine sand and finer would pass; medium sand and coarser would be retained; fine sand is split at about 150 µm. Real sieving also depends on particle shape, sieving time and the opening tolerance of the cloth.
With a typical 0.1 mm wire, 100 mesh has roughly 36% open area. Thicker wire lowers the open area and the opening size.