Food, drink & pharmaMaker spec
Coffee grind sifting
Sieves from 200 to 1600 µm
Coffee sifters stack interchangeable sieves between 200 and 1600 µm to isolate a target grind range.
Opening range200 µm – 1.6 mm
01 — StandardWhat is 18 mesh in microns?
A US standard No. 18 test sieve (ASTM E11) has a nominal opening of 1,000 µm.
02 — Specifications18 mesh specifications
| Opening (microns) | 1,000 µm |
| Opening (millimeters) | 1 mm |
| Opening (inches) | 0.0394 in |
| US standard sieve | No. 18 |
| Tyler equivalent | 16 mesh |
| Pitch (wire center to center) | 1,560 µm |
| Typical wire diameter | 0.56 mm |
| Approx. open area | 41% |
03 — ApplicationsWhat is 18 mesh used for?
A 1,000 µm opening sits exactly on the Wentworth boundary between coarse sand and very coarse sand. Comparing grain size with the nominal opening only: grains up to and including 1,000 µm would pass; grains larger than 1,000 µm would be retained. Real sieving also depends on particle shape, sieving time and the opening tolerance of the cloth.
These applications commonly use a 18 mesh count or an opening near 1,000 µm:
Ranges show common practice with sources on the mesh size by application page — always check your equipment maker's recommendation.
04 — CalculationHow the 18 mesh value is calculated
The name "18 mesh" suggests 18 openings per inch, i.e. a pitch of 25,400 ÷ 18 = 1,411.1 µm. Standard test sieves, however, are defined by their opening, not by the count: a 1,000 µm opening woven with the typical 0.56 mm wire gives a real pitch of 1,000 + 560 = 1,560 µm, which is about 16.3 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 |
|---|---|---|---|
| 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 |
| 20 mesh | 850 | 0.85 | 0.0335 |
| 25 mesh | 710 | 0.71 | 0.028 |
| 30 mesh | 600 | 0.6 | 0.0236 |
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 18 mesh?
18 mesh is 1,000 µm, which is 1 mm or 0.0394 inches.
What size particles pass through a 18 mesh screen?
In a simplified comparison with the nominal opening, particles smaller than about 1,000 µm can pass a 18 mesh screen. A 1,000 µm opening sits exactly on the Wentworth boundary between coarse sand and very coarse sand. Comparing grain size with the nominal opening only: grains up to and including 1,000 µm would pass; grains larger than 1,000 µm would be retained. Real sieving also depends on particle shape, sieving time and the opening tolerance of the cloth.
What is the open area of 18 mesh?
With a typical 0.56 mm wire, 18 mesh has roughly 41% open area. Thicker wire lowers the open area and the opening size.