US Mesh vs. Micron
The chart below roughly converts between US mesh, microns, and fractions of an inch.
Micron is the unit of measure of length most frequently used to describe very small particle sizes. The term micron is interchangeable with micrometer. A micron/micrometer is defined as one-millionth of a meter. There are 25,400 microns in one inch. The official symbol for the micron or micrometer is μm, or simply μ.
*In liquid filtration, a smaller micron rating means the filter is more efficient at collecting smaller contaminants. Generally, the micron rating of a filter correlates to the ability of the filter to remove particles of its rated micron size and larger.
Mesh size refers to the number of openings per inch of screen, measured starting at the center of one wire. Similarly, in liquid filtration, the number of openings in a monofilament mesh fabric is the reference. Mesh sizes are conversely related to particle size. A larger mesh number means that there are a greater number of openings in one inch, so only small particles could pass through. A smaller mesh number means that with fewer openings in one inch, larger particles could pass through. Mesh ratings are not always precise because they are dependent on the diameter of the screen material.