ION EXCHANGE Update 19 Jun 2015

Mesh size of sieve openings
(particle size)

In the USA, ion exchange resin bead size is often expressed in mesh. This table shows the corresponding sieve opening in millimetres. Historically, there were other mesh definitions (such as Tyler or BSS), but they are no longer in use.

Most commercial resins have a particle size of 0.3 to 1.2 mm, which corresponds to 16 to 50 mesh (US). Uniform resins such as AmberjetTM, Dowex MonosphereTM or Lewatit MonoplusTM have a much narrower particle size distribution. Chromatographic grade resins are usually finer (150 to 300 µm i.e. 50 to 100 mesh) with a narrow distribution as well.


US mesh N° mm
400 0.038
325 0.045
270 0.053
230 0.063
200 0.075
170 0.090
140 0.106
120 0.125
100 0.150
80 0.180
70 0.212
60 0.250
50 0.300
45 0.355
40 0.425
35 0.500
30 0.600
25 0.710
20 0.850
18 1.000
16 1.180
14 1.400
12 1.700
10 2.000
8 2.360
6 3.350
4 4.750

See also the "Resin properties" page.

© François de Dardel