Desiccant Mesh Size Explained

What Is "Mesh"?

The mesh size system is a standardized way to describe the particle size of granular materials, including bulk desiccants like silica gel and molecular sieves. It is based on the number of openings in a linear inch of wire mesh used in a sieve for sorting these kinds of materials. The number of openings is inversely proportional to the size of the openings, so larger mesh size numbers indicate smaller granules. For example, a mesh with 4 openings per inch will allow much larger particles to pass through than a mesh with 100 openings per inch.

Bulk desiccant listings will often include particle sizes in millimeters, microns, and/or inches along with a mesh size. The mesh size corresponds to the largest desiccant bead diameter for that product. For instance, 4 mesh indicates particles that are 4.75 mm or smaller, and 100 mesh corresponds to particles that are 0.149 mm or smaller. See the accompanying table for a range of common U.S. mesh sizes and corresponding particle sizes.

Desiccants are also listed as falling within a range of mesh sizes, usually expressed as “8x12 mesh” or “8-12 mesh,” for example. This indicates that the desiccant beads fit through the first mesh size, but not the second. An 8x12 mesh desiccant will therefore include beads that are approximately 1.7 to 2.3 mm in diameter. See the table at the bottom of this page for an extensive list of U.S. mesh sizes.

Why Mesh Size Matters

1. Adsorption Rate: Smaller particles (higher mesh) have a higher surface-area-to-volume ratio, allowing them to absorb moisture faster.
2. Pressure Drop: Larger particles (lower mesh) allow for easier airflow between them. This is critical for industrial compressed air systems where maintaining high flow rates is necessary.
3. Dusting & Handling: Very fine mesh sizes can create more dust and may require specialized containment to prevent the desiccant from leaking into the system.

U.S. Mesh Size	Applications	Reasons
4x8 Mesh ≈ 2.4–4.8 mm Large beads	Tank and transformer breathers Compressed air dryers (twin tower / regenerative) Natural gas / industrial gas drying Bulk storage protection (drums, tanks)	Very low pressure drop (air flows easily), high crush strength for tall packed beds, minimal dust carryover
6x12 Mesh ≈ 1.7–3.3 mm Medium-large	Desiccant packets (sachets) Pharmaceutical canisters General-purpose moisture control in packaging Some reusable canister-style desiccants	Good balance of surface area vs. low dust, flows well in automated filling lines, more robust than smaller granules
8x16 Mesh ≈ 1.2–2.4 mm Medium beads	Electronics packaging Military / spec packaging (MIL-D-3464 style) Consumer goods moisture protection Optical equipment, tools, spare parts	Higher adsorption rate than 6–12 mesh, still manageable dust levels, widely accepted “standard” size in specs
16x30 Mesh ≈ 0.6–1.2 mm Small granules	Laboratory drying columns Indicator silica gel blends Small sealed enclosures needing fast response Specialty cartridges and instruments	Faster adsorption kinetics (more surface area); better for low humidity, small volume environments Drawbacks: more dust, reduced airflow, lower mechanical durability
30x60 Mesh ≈ 0.25–0.6 mm Fine grains	Laboratory and analytical drying Chromatography and separation media Small cartridges and instrument dryers Specialty packaging applications	Faster adsorption, better contact efficiency, compact bed performance Drawbacks: low airflow, dust handling challenges, requires containment
-200 Mesh < ~0.07 mm Powder / flour	Additives in plastics, coatings, adhesives Catalyst or adsorption processes Specialty chemical formulations Embedded moisture control systems	Maximum surface area, can be mixed directly into materials Drawbacks: dusting, caking, poor flowability, containment challenges

The table below shows standard U.S. mesh sizing and the corresponding diameters for all types of particulate products.

U.S. MESH	MILLIMETERSMM	MICRONS	INCHES
3	6.730	6730	0.2650
4	4.760	4760	0.1870
5	4.000	4000	0.1570
6	3.360	3360	0.1320
7	2.830	2830	0.1110
8	2.380	2380	0.0937
10	2.000	2000	0.0787
12	1.680	1680	0.0661
14	1.410	1410	0.0555
16	1.190	1190	0.0469
18	1.000	1000	0.0394
20	0.841	841	0.0331
25	0.707	707	0.0280
30	0.595	595	0.0232
35	0.500	500	0.0197
40	0.400	400	0.0165
45	0.354	354	0.0138
50	0.297	297	0.0117
60	0.250	250	0.0098
70	0.210	210	0.0083
80	0.177	177	0.0070
100	0.149	149	0.0059
120	0.125	125	0.0049
140	0.105	105	0.0041
170	0.088	88	0.0035
200	0.074	74	0.0029
230	0.063	63	0.0024
270	0.053	53	0.0021
325	0.044	44	0.0017
400	0.037	37	0.0015