01 — FormulasWire mesh formulas
Pitch (µm) = 25,400 ÷ mesh count Opening (µm) = pitch − wire diameter (µm) Open area (%) = (opening ÷ pitch)² × 100Worked example
100 mesh with 0.10 mm (100 µm) wire: pitch = 25,400 ÷ 100 = 254 µm. Opening = 254 − 100 = 154 µm(0.154 mm). Open area = (154 ÷ 254)² × 100 ≈ 37%.
02 — ReferenceTypical wire diameters for standard sieves
| Mesh (US sieve No.) | Opening | Typical wire | Open area |
|---|---|---|---|
| 20 | 850 µm | 0.5 mm | 40% |
| 50 | 300 µm | 0.2 mm | 36% |
| 100 | 150 µm | 0.1 mm | 36% |
| 200 | 75 µm | 0.05 mm | 36% |
Typical wire diameters per ASTM E11. See the full chart for every size.
03 — AccuracyNotes on accuracy
- The formulas assume square, plain-weave mesh (same mesh count and wire in both directions).
- Twill and Dutch weaves, rectangular openings and welded mesh need different calculations.
- Commercial wire cloth has manufacturing tolerances; confirm critical openings with your supplier.
04 — FAQFrequently asked questions
How do you calculate wire mesh opening size?
Opening = (1 ÷ mesh count) − wire diameter, in inches. In microns: 25,400 ÷ mesh − wire diameter (µm).
How do you calculate open area of wire mesh?
For square plain-weave mesh: open area % = (opening × mesh ÷ 25,400)² × 100, with the opening in microns. Equivalently, (opening ÷ pitch)² × 100.
Does thicker wire make the mesh finer?
Yes. At the same mesh count, thicker wire leaves a smaller opening and lower open area, but makes the screen stronger and longer-lasting.