| Mesh | Wire (mm) | Opening (µm) | Open Area (%) | Typical garden use |
|---|---|---|---|---|
| 20 | 0.40 | ~870 | ~56 | Mulch screening, large grit removal |
| 40 | 0.30 | ~335 | ~44 | Compost sifting, general intake screening |
| 80 | 0.20 | ~118 | ~34 | Fine drip filtration and emitter protection |
| 120 | 0.15 | ~62 | ~30 | Very fine filtration; more frequent cleaning |
- Pitch (inch) = 1 ÷ Mesh
- Wire (inch) = Wire diameter (mm) ÷ 25.4
- Opening (inch) = Pitch − Wire
- Opening (microns) = Opening (inch) × 25,400
- Open area (%) = ( Opening ÷ (Opening + Wire) )² × 100
- Select Mesh → Microns when you know the mesh count.
- Select Microns → Mesh when you have a filtration target.
- Enter a realistic wire diameter from the screen specification.
- Press Calculate to see results above the form.
- Use Download CSV or Download PDF for records.
Mesh count and micron rating relationship
Mesh is the number of openings per linear inch. Higher mesh usually means smaller openings and finer filtration. This calculator estimates opening size in microns (µm) from pitch (1 ÷ mesh) minus wire thickness, so the result improves when you enter the actual wire diameter. Use conversions mainly to compare options consistently.
Why wire diameter changes results
Wire diameter reduces the free opening and changes stiffness. For the same mesh, thicker wire produces a smaller micron opening and lowers open area, which can reduce flow and increase clogging risk. Garden screens often use 0.15–0.40 mm wire; unrealistic combinations are flagged when the opening becomes very small.
Open area, flow rate, and pressure drop
Open area is computed with a square ratio: (opening ÷ (opening + wire))² × 100. More open area generally means higher flow and less rapid blockage, but less fine capture. In drip irrigation, select a micron target that protects emitters without creating a constant pressure-loss point.
Practical filtration targets in gardens
As a field guide, 500–1000 µm fits coarse intake screening, 200–500 µm works for many pumps and general filtration, and 80–200 µm is common for micro-sprinklers and drip lines. Use Microns → Mesh to estimate the needed mesh, then confirm the product’s published micron rating. Very fine targets may need a larger filter body. Match screen choice to water source, seasonal debris load, and emitter tolerance.
Cleaning intervals and clogging risk
Finer screens capture more silt, algae, and biofilm, so cleaning frequency rises as micron size drops. For dirty sources, staged filtration helps: a coarse pre-screen before the pump and a finer screen near emitters. Use the calculator’s open area and notes to anticipate maintenance and backflushing needs.
1) What mesh size should I use for drip irrigation?
Many drip systems perform well around 120–200 microns, depending on emitter design and water quality. Use the microns target recommended by your emitter or filter manufacturer, then estimate the matching mesh and confirm the screen’s published rating.
2) Does higher mesh always mean better filtration?
Higher mesh usually means smaller openings, but performance also depends on wire diameter and screen construction. A very fine screen can clog quickly and reduce flow. Balance micron capture with open area and cleaning practicality.
3) Why does the calculator ask for wire diameter?
Wire thickness changes the opening size and the percentage of open area. Two screens labeled with the same mesh can have different wire diameters, producing different micron openings and different flow behavior.
4) What if my result shows a negative or near-zero opening?
That combination is physically unrealistic because the wire is too thick for the selected mesh. Choose a lower mesh, select a thinner wire option, or switch to a different screen style designed for fine filtration.
5) How accurate are mesh-to-micron conversions?
They are estimates based on square woven wire geometry. Real products may differ due to weave, manufacturing tolerances, and how “micron rating” is defined. Use the results for planning and comparison, then verify with supplier specifications.
6) How often should I clean a fine screen filter?
Cleaning depends on water source and runtime. Fine screens can require frequent rinsing or backflushing, especially with algae or silt. Monitor pressure drop and flow; when performance declines, clean the screen before irrigating again.