Question 1

What does mesh count mean for wire mesh?

Accepted Answer

Mesh count is the number of openings per linear inch. A 100-mesh screen has 100 openings per inch. Higher mesh count means smaller openings and finer filtration. The actual opening size depends on both the mesh count and the wire diameter.

Question 2

How do I convert mesh count to microns?

Accepted Answer

The opening size in mm = 25.4 / mesh − wire diameter. Multiply by 1,000 to get microns. For example, 100-mesh with 0.10 mm wire gives an opening of 0.154 mm = 154 µm. The ASTM E11 sieve table gives nominal openings for standard sieve sizes.

Question 3

What is the ASTM E11 standard for wire mesh sieves?

Accepted Answer

ASTM E11 specifies standard wire cloth test sieves used in particle size analysis. It defines nominal opening sizes from 38 µm (400 mesh) to 4,750 µm (4 mesh), with tolerances on wire diameter and opening uniformity. The same designations are used in ISO 565.

Question 4

Why does the same mesh count have different opening sizes from different suppliers?

Accepted Answer

Opening size equals 25.4/mesh − wire diameter. Different wire diameters — even within tolerance — produce different opening sizes for the same mesh count. Always specify both mesh count and wire diameter together to avoid ambiguity when ordering.

Mesh	Nominal opening (µm)	≈ mm
4	4750	4.75
6	3350	3.35
8	2360	2.36
10	2000	2.00
12	1700	1.70
14	1400	1.40
16	1180	1.18
18	1000	1.00
20	850	0.850
25	710	0.710
30	600	0.600
35	500	0.500
40	425	0.425
45	355	0.355
50	300	0.300
60	250	0.250
70	212	0.212
80	180	0.180
100	150	0.150
120	125	0.125
140	106	0.106
170	90	0.090
200	75	0.075
230	63	0.063
270	53	0.053
325	45	0.045
400	38	0.038

Mesh ↔ Micron Conversion

ASTM E11 Standard Sieve Series (nominal)

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