Particle size comparison chart

There are a number of units and scales commonly used to measure particle size. These either refer to average particle diameter measured in units of length, typically microns, or refer to a smallest mesh size through which the particles will pass. The following table sets out conversions between a variety of systems:   

US MESH TYLER SCREEN BSS MESH MICRONS INCHES MILLIMETRES EXAMPLE
18 16 16 1000 0.0394 1.000  
20 20 18 841 0.0331 0.841  
25 24 22 707 0.0280 0.707 beach sand
30 28 25 595 0.0232 0.595  
35 32 30 500 0.0197 0.500  
40 35 36 400 0.0165 0.400  
45 48 44 354 0.0138 0.354  
50 48 52 297 0.0117 0.297  
60 60 60 250 0.0098 0.250 fine sand
70 65 72 210 0.0083 0.210  
80 80 85 177 0.0070 0.177  
100 100 100 149 0.0059 0.149  
120 115 120 125 0.0049 0.125  
140 150 - 105 0.0041 0.105  
170 170 170 88 0.0035 0.088  
200 200 200 74 0.0029 0.074 portland cement
230 250 240 63 0.0024 0.063  
270 270 - 53 0.0021 0.053  
325 325 350 44 0.0017 0.044  
400 400 - 37 0.0015 0.037 plant pollen
550 - - 25 0.0009 0.0025  
800 - - 15 0.0006 0.015  
1200 - - 12 0.0005 0.012  
1250 - - 10 0.0004 0.010  
2500 - - 10 0.0004 0.010 large bacteria
4800 - - 2 0.0001 0.002 smoke particle