MESH TO MICRON CONVERSION CHART

U.S. MESH

INCHES

MICRONS

MILLIMETERS

3

0.2650

6730

6.730

4

0.1870

4760

4.760

5

0.1570

4000

4.000

6

0.1320

3360

3.360

7

0.1110

2830

2.830

8

0.0937

2380

2.380

10

0.0787

2000

2.000

12

0.0661

1680

1.680

14

0.0555

1410

1.410

16

0.0469

1190

1.190

18

0.0394

1000

1.000

20

0.0331

841

0.841

25

0.0280

707

0.707

30

0.0232

595

0.595

35

0.0197

500

0.500

40

0.0165

400

0.400

45

0.0138

354

0.354

50

0.0117

297

0.297

60

0.0098

250

0.250

70

0.0083

210

0.210

80

0.0070

177

0.177

100

0.0059

149

0.149

120

0.0049

125

0.125

140

0.0041

105

0.105

170

0.0035

88

0.088

200

0.0029

74

0.074

230

0.0024

63

0.063

270

0.0021

53

0.053

325

0.0017

44

0.044

400

0.0015

37

0.037

Mesh Sizes and Microns

What does mesh size mean?  Figuring out mesh sizes is simple.  All you do is count the number of openings in one inch of screen (in the United States, anyway.)  The number of openings is the mesh size.  So a 4-mesh screen means there are four little squares across one linear inch of screen.  A 100-mesh screen has 100 openings, and so on.  As the number describing the mesh size increases, the size of the particles decreases.   Higher numbers equal finer material.  Mesh size is not a precise measurement of particle size.

What do the minus (-) and plus (+) plus signs mean when describing mesh sizes?  Here’s a simple example of how they work.  –200-mesh would mean that all particles smaller than 200-mesh would pass through. +200 mesh means that all the particles 200-mesh or larger are retained.

How fine do screens get?  That depends on the wire thickness.  If you think about it, the finer the weave, the closer the wires get together, eventually leaving no space between them at all. For this reason, beyond 325-mesh particle size is usually described in “microns.”

What is a micron?  A micron is another measurement of particle size.  A micron is one-millionth of a meter or one twenty-five thousandth of an inch.

Sieve Mesh #

Inches

Microns

Typical Material

14

.0555

1400

-

28

.028

700

Beach Sand

60

.0098

250

Fine Sand

100

.0059

150

-

200

.0029

74

Portland Cement

325

.0017

44

Silt

400

.0015

37

Plant Pollen

(1200)

.0005

12

Red Blood Cell

(2400)

.0002

6

-

(4800)

.0001

2

Cigarette Smoke

The mesh numbers in parentheses are too small to exist as actual screen sizes; they are estimates included for reference.

This table was adapted from a post made by Ken Kosanke to the PML and previously published in a PGII Bulletin. It has also been modified and edited for use on this site.