Two numbers describe almost every wire mesh filter: mesh count and micron rating. Confusing them is the single most common cause of ordering the wrong part. This guide explains both, shows how they convert, and tells you which one to give us.
What mesh count means
Mesh count is the number of openings per linear inch of woven cloth. A 100-mesh screen has 100 openings per inch. Higher mesh count means smaller openings — but only if the wire diameter is also specified, because thicker wire eats into the opening for the same count.
Why wire diameter changes everything
Two 100-mesh screens can have very different actual openings and open areas:
| 100-mesh screen | Wire diameter | Actual opening | Open area |
|---|---|---|---|
| Coarse wire | 0.10 mm | ~0.15 mm | lower |
| Fine wire | 0.06 mm | ~0.19 mm | higher |
That is why “100 mesh” alone is not a complete specification. Open area also drives flow: for the same mesh count, finer wire gives more open area and less pressure drop.
What micron rating means
The micron rating is the real size of particle the filter will stop, in micrometres (1 micron = 0.001 mm). This is what actually matters for your process. Because it already accounts for the true opening, it is the safest single number you can give us.
Approximate conversions (plain-weave)
| Mesh | Approx. micron |
|---|---|
| 50 | ~280 |
| 100 | ~140 |
| 200 | ~74 |
| 325 | ~44 |
| below ~44 micron | fine “market grade” or sintered multilayer |
These are guideline values for plain-weave cloth; exact openings depend on wire diameter and weave. Below ~44 micron, single-layer plain weave becomes impractical and we move to fine market-grade weave or a sintered multilayer build.
Which number should you give us?
Tell us whichever you know:
- If you know the particle you must retain (or pass), give the micron figure — it is unambiguous.
- If you have used a mesh count before and it worked, give that plus the wire diameter if you have it.
We convert to the correct weave and wire diameter and confirm the open area for your flow rate. Grade (304 vs 316L) is a separate decision — see 304 vs 316L — it controls corrosion life, not rating.
Common mistakes
- Giving mesh count without wire diameter and expecting an exact micron result.
- Confusing nominal and absolute ratings — sintered media gives a far more absolute cut than a single woven layer at the same nominal micron.
- Ignoring open area — the finest mesh that “works” may choke your flow; tell us the flow rate so we balance rating against pressure drop.
A practical tip
If you must retain 50-micron particles reliably under pressure, do not simply order “270 mesh.” Tell us “retain 50 micron at X L/min and Y bar,” and we will propose either a fine woven weave or a multilayer/sintered disc that holds that cut when the pressure fluctuates.
Send your target retention size and flow rate and we will propose the exact mesh specification. Request a Quote →