Mesh vs Micron: The Complete Conversion Guide

Nothing causes more silent spec errors between buyer and supplier than mesh numbers. A US 100 mesh is not a Tyler 100 mesh, neither equals ISO 100, and all of them describe holes, not particles. Five minutes here will save you a container of off-spec product.

Why mesh runs “backwards”

Mesh count = wires per inch. More wires per inch means more wire and smaller apertures — so 500 mesh is far finer than 50 mesh. The aperture (hole) is what you actually care about, and it depends on wire diameter, which differs by standard. That is why serious specs are written in microns and merely referenced to mesh.

The working table (US standard, aperture μm)

Mesh	Micron	Typical product example
10	2000	Granule scalping
20	841	Sugar guard cut
40	420	Semolina cuts
60	250	Flour top-cut
100	149	Icing sugar
200	74	Pigment cuts
325	44	Metal powder guard
500	25	Fine pharma / ultrasonic class

Use the interactive version on our tools page — it converts in both directions and marks which cuts need ultrasonic assistance.

Three traps that cost real money

• Standards mismatch. US 325 mesh = 44 μm; Tyler 325 = 43 μm; ISO-325 equivalents differ again. Always write both mesh and μm on POs, e.g. “325 mesh / 44 μm, US standard”.
• Nominal vs effective aperture. Woven mesh tolerates ±8% variation mid-range and more at the extremes. If your spec is tight, specify “certified test sieve grade” cloth for reference sieves and production grade for throughput sieves — and know which one you are buying.
• Open area vs mesh count. At fine mesh, open area collapses (500 mesh ≈ 20% open area in production weave). Throughput falls with it — the honest reason 500-mesh cuts run at tens of kg/h, not tons.

Rule of thumb for machine sizing

Every halving of aperture roughly halves achievable throughput per m² at equal motion energy. When a customer tells us “same machine, just change the mesh from 100 to 200”, the physics replies: budget half the flow, or twice the deck area, or add ultrasonic.