Buyers ask for wire mesh two ways — by mesh count (openings per inch) or by micron (the size of the opening). The two are related but not interchangeable, because the opening also depends on how thick the wire is. This chart gives the standard nominal conversions, and the notes below explain how to read them so you order the right cloth the first time.
The conversion chart
Standard market values for plain-weave woven wire mesh. These are nominal openings for the common wire diameter at each count — the actual aperture shifts with wire diameter (see the next section).
| Mesh (per inch) | Aperture (micron) | Aperture (mm) | Typical use |
|---|---|---|---|
| 10 | 2000 | 2.00 | Coarse sieving, guarding |
| 14 | 1400 | 1.40 | Aggregate, grain |
| 20 | 840 | 0.84 | General sieving |
| 30 | 595 | 0.595 | Sieving, straining |
| 40 | 420 | 0.420 | Straining |
| 50 | 297 | 0.297 | Fine sieving |
| 60 | 250 | 0.250 | Fine sieving |
| 80 | 177 | 0.177 | Filtration |
| 100 | 149 | 0.149 | Filtration |
| 120 | 125 | 0.125 | Fine filtration |
| 150 | 105 | 0.105 | Fine filtration |
| 200 | 74 | 0.074 | Fine filtration |
| 250 | 63 | 0.063 | Very fine filtration |
| 325 | 44 | 0.044 | Very fine filtration |
| 400 | 37 | 0.037 | Micro-filtration |
Nominal values for standard wire diameters; treat them as a reference, not a guarantee. For an exact opening, confirm the wire diameter — or just tell us the micron you need and we match the weave.
Why mesh count alone isn't enough
Mesh count only tells you how many wires sit in one inch. The opening is what's left after the wires take up their share of that inch:
Aperture = (25.4 ÷ mesh count) − wire diameter (all in mm)
So a single mesh count can give very different openings depending on the wire. The same count woven with a thicker wire has a smaller opening, a stronger, longer-wearing cloth and lower open area; a thinner wire opens it up and flows more, but wears faster. That trade-off is the whole game in filtration and screening.
Aperture vs mesh vs micron — reading a spec
- Mesh count — wires (or openings) per linear inch. Higher count = finer.
- Aperture / opening — the clear gap between adjacent wires, in mm or microns.
- Micron — just the aperture expressed in microns (1 mm = 1000 micron).
- Wire diameter — the thickness of the wire; sets strength, wear life and open area.
Worked example
Take a 100-mesh cloth. The pitch is 25.4 ÷ 100 = 0.254 mm (254 micron). Woven with 0.10 mm wire, the opening is 0.254 − 0.10 = 0.154 mm (154 micron). Drop to 0.065 mm wire and the opening grows to 0.189 mm (189 micron) — same "100 mesh", a 35-micron difference and noticeably more open area. This is why we always confirm wire diameter before quoting a filtration cloth.
Specifying for filtration vs sieving
For sieving and grading, mesh count usually does the job — you're separating particles well above the opening. For filtration, specify the micron you need to retain, and decide whether you want a plain square weave (defined openings) or a dutch weave (much finer effective filtration than the count suggests, used for fine and absolute-rated work). Twill weave lets you go finer with heavier wire for strength.
Once you know the opening, see our SS wire mesh range (304 / 316) or, for screening duty, crusher and vibrating screen mesh. Not sure on grade? Read SS 304 vs 316 — which grade to use.