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. 8 test sieve (ASTM E11) has a nominal opening of 2,360 µm.
| Opening (microns) | 2,360 µm |
| Opening (millimeters) | 2.36 mm |
| Opening (inches) | 0.0929 in |
| US standard sieve | No. 8 |
| Tyler equivalent | 8 mesh |
| Pitch (wire center to center) | 3,360 µm |
| Typical wire diameter | 1 mm |
| Approx. open area | 49% |
A 2,360 µm opening falls within the granules (2 mm–4 mm) class of the Wentworth grain-size scale. Comparing grain size with the nominal opening only: very coarse sand and finer would pass; pebbles and coarser would be retained; granules is split at about 2,360 µm. Real sieving also depends on particle shape, sieving time and the opening tolerance of the cloth.
These applications commonly use a 8 mesh count or an opening near 2,360 µm:
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).
#8 hardware cloth (8 per inch)
#8 hardware cloth (8 openings per inch) lets Varroa mites that drop off bees fall out of the hive while keeping bees in.
Ranges show common practice with sources on the mesh size by application page — always check your equipment maker's recommendation.
The name "8 mesh" suggests 8 openings per inch, i.e. a pitch of 25,400 ÷ 8 = 3,175 µm. Standard test sieves, however, are defined by their opening, not by the count: a 2,360 µm opening woven with the typical 1 mm wire gives a real pitch of 2,360 + 1,000 = 3,360 µm, which is about 7.6 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 |
|---|---|---|---|
| 4 mesh | 4,750 | 4.75 | 0.187 |
| 8 mesh | 2,360 | 2.36 | 0.0929 |
| 10 mesh | 2,000 | 2 | 0.0787 |
| 12 mesh | 1,700 | 1.7 | 0.0669 |
| 14 mesh | 1,400 | 1.4 | 0.0551 |
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.
8 mesh is 2,360 µm, which is 2.36 mm or 0.0929 inches.
In a simplified comparison with the nominal opening, particles smaller than about 2,360 µm can pass a 8 mesh screen. A 2,360 µm opening falls within the granules (2 mm–4 mm) class of the Wentworth grain-size scale. Comparing grain size with the nominal opening only: very coarse sand and finer would pass; pebbles and coarser would be retained; granules is split at about 2,360 µm. Real sieving also depends on particle shape, sieving time and the opening tolerance of the cloth.
With a typical 1 mm wire, 8 mesh has roughly 49% open area. Thicker wire lowers the open area and the opening size.