01 — StandardWhat is 12 mesh in microns?
A US standard No. 12 test sieve (ASTM E11) has a nominal opening of 1,700 µm.
02 — Specifications12 mesh specifications
| Opening (microns) | 1,700 µm |
| Opening (millimeters) | 1.7 mm |
| Opening (inches) | 0.0669 in |
| US standard sieve | No. 12 |
| Tyler equivalent | 10 mesh |
| Pitch (wire center to center) | 2,500 µm |
| Typical wire diameter | 0.8 mm |
| Approx. open area | 46% |
03 — ApplicationsWhat is 12 mesh used for?
A 1,700 µm opening falls within the very coarse sand (1 mm–2 mm) class of the Wentworth grain-size scale. Comparing grain size with the nominal opening only: coarse sand and finer would pass; granules and coarser would be retained; very coarse sand is split at about 1,700 µm. Real sieving also depends on particle shape, sieving time and the opening tolerance of the cloth.
We have no sourced application data for openings this size yet.
Ranges show common practice with sources on the mesh size by application page — always check your equipment maker's recommendation.
04 — CalculationHow the 12 mesh value is calculated
The name "12 mesh" suggests 12 openings per inch, i.e. a pitch of 25,400 ÷ 12 = 2,116.7 µm. Standard test sieves, however, are defined by their opening, not by the count: a 1,700 µm opening woven with the typical 0.8 mm wire gives a real pitch of 1,700 + 800 = 2,500 µm, which is about 10.2 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.
05 — CompareNearby mesh sizes
| 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 |
| 16 mesh | 1,180 | 1.18 | 0.0465 |
| 18 mesh | 1,000 | 1 | 0.0394 |
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.
06 — FAQFrequently asked questions
How many microns is 12 mesh?
12 mesh is 1,700 µm, which is 1.7 mm or 0.0669 inches.
What size particles pass through a 12 mesh screen?
In a simplified comparison with the nominal opening, particles smaller than about 1,700 µm can pass a 12 mesh screen. A 1,700 µm opening falls within the very coarse sand (1 mm–2 mm) class of the Wentworth grain-size scale. Comparing grain size with the nominal opening only: coarse sand and finer would pass; granules and coarser would be retained; very coarse sand is split at about 1,700 µm. Real sieving also depends on particle shape, sieving time and the opening tolerance of the cloth.
What is the open area of 12 mesh?
With a typical 0.8 mm wire, 12 mesh has roughly 46% open area. Thicker wire lowers the open area and the opening size.
Why do some charts list 12 mesh as 1,400 µm?
Those charts use the older Tyler scale, where 12 mesh corresponds to 1,400 µm (ASTM No. 14). In the US standard (ASTM E11) series, No. 12 is 1,700 µm.