Mesh to Micron / MM Conversion Chart & Calculator | M&C

Q: Does a higher mesh number mean finer particles?

Yes. Mesh counts openings per inch, so a higher number means smaller openings and finer particles.

Q: What is the difference between mesh and micron?

Mesh is the count of openings per inch; micron is the physical opening size in micrometers.

Q: What is 60 mesh in microns and mm?

60 mesh is 250 microns, or 0.25 mm.

Q: What is 20 mesh in mm?

20 mesh is 850 microns, or 0.85 mm.

Q: How do I choose the right mesh for filter cloth or a screen?

Start from the particle size in microns you must retain or pass, choose the closest standard mesh, and allow a coarser margin for sticky high-clay feeds to prevent blinding.

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Mesh Conversion Calculator

Mesh

mesh

Micron

μm

Millimeter

Inch

Enter any one value — the other three convert automatically. Standard screens match the ASTM E11 chart below.

ASTM E11 Mesh to Micron Conversion Chart

Higher mesh number = smaller opening.

Mesh	Inch (in)	Micron (μm)	Millimeter (mm)
2.5 mesh	0.3150	8000	8.00
3 mesh	0.2638	6700	6.70
3.5 mesh	0.2205	5600	5.60
4 mesh	0.1870	4750	4.75
5 mesh	0.1575	4000	4.00
6 mesh	0.1319	3350	3.35
7 mesh	0.1102	2800	2.80
8 mesh	0.09291	2360	2.36
10 mesh	0.07874	2000	2.00
12 mesh	0.06693	1700	1.70
14 mesh	0.05512	1400	1.40
16 mesh	0.04646	1180	1.18
18 mesh	0.03937	1000	1.00
20 mesh	0.03346	850	0.850
25 mesh	0.02795	710	0.710
30 mesh	0.02362	600	0.600
35 mesh	0.01969	500	0.500
40 mesh	0.01673	425	0.425
45 mesh	0.01398	355	0.355
50 mesh	0.01181	300	0.300
60 mesh	0.009843	250	0.250
70 mesh	0.008268	210	0.210
80 mesh	0.007087	180	0.180
100 mesh	0.005906	150	0.150
120 mesh	0.004921	125	0.125
140 mesh	0.004173	106	0.106
170 mesh	0.003543	90	0.090
200 mesh	0.002953	75	0.075
230 mesh	0.002480	63	0.063
270 mesh	0.002087	53	0.053
325 mesh	0.001772	45	0.045
400 mesh	0.001496	38	0.038

What Is Mesh Size and How to Read It

Mesh size refers to the number of openings in one linear inch of a screen, measured from the center of any wire to the center of the wire one inch away. A 100-mesh screen has 100 openings per inch; a 200-mesh screen has 200. Because the mesh number counts openings, a higher mesh number means a smaller opening and finer particles pass through.

Mesh vs Micron vs Millimeter

Micron (μm) is the actual opening size: 1 μm = 0.001 mm.
Millimeter (mm) is the same opening in millimeters.
Inch (in) is the opening in inches: 1 in = 25.4 mm.
Standard screens follow ASTM E11 (US) / ISO 3310 (metric).
For non-standard values, opening (mm) ≈ 25.4 / mesh.

Where These Conversions Are Used

Selecting vibrating screen mesh for sand and aggregate grading.
Sizing filter press cloth and filter bags.
Choosing PU or rubber screen panels for a cut point.
Reading laboratory sieve analysis and PSD reports.
Specifying hydrocyclone and fine-sand recovery cut points.

Worked Example: Reading a PSD Report

If a customer’s report states that product is “minus 200 mesh,” it means every particle passes a 200-mesh screen with a 75 μm (0.075 mm) opening. A target such as “80% passing 10 mesh (2.0 mm)” means 80% of the material is finer than 2.0 mm. Use the calculator above to turn any mesh number into the μm or mm value used in equipment sizing.

Frequently Asked Questions

What is 200 mesh in microns and mm?

A 200-mesh screen has an opening of 75 microns (0.075 mm) under ASTM E11. “Minus 200 mesh” material passes through a 75 μm opening.

What is 325 mesh in mm?

325 mesh equals 45 microns, or 0.045 mm. This is the finest commonly used test sieve in mineral and powder processing.

What is 100 mesh in microns?

100 mesh corresponds to 150 microns (0.15 mm). Older charts sometimes list 165 μm, which is not the current ASTM value.

Does a higher mesh number mean finer particles?

Yes. Mesh counts openings per inch, so more openings per inch means each opening is smaller. 40 mesh (425 μm) is coarse; 200 mesh (75 μm) is fine.

What is the difference between mesh and micron?

Mesh is a count of openings per inch, while micron is the physical size of one opening in micrometers. The mesh number alone does not give an exact size without a standard such as ASTM E11 or ISO, because wire diameter also affects the opening.

What is 60 mesh in microns and mm?

60 mesh = 250 microns = 0.25 mm. This is a common cut point for fine sand and concrete-sand grading.

What is 20 mesh in mm?

20 mesh = 850 microns = 0.85 mm. The theoretical 25.4 / mesh value (1.27 mm) is not used for standard screens; the ASTM nominal opening is 0.85 mm.

How do I choose the right mesh for filter cloth or a screen?

Start from the particle size you must retain or pass (in μm), then choose the standard mesh closest to that cut point. For sticky or high-clay feeds, allow a margin and select a slightly coarser cloth to reduce blinding. Our engineers can confirm the cut point from your sieve analysis — send us your PSD data.