Mesh to Micron Converter

How to use the mesh to micron converter

What this calculator does

This calculator translates a selected U.S. mesh number into a commonly tabulated nominal sieve opening. It reports the opening in micrometres, millimetres, and inches, and shows nearby standard sizes for quick comparison. This is useful for particle-size screening, powder handling, filtration discussions, laboratory sieve selection, and checking supplier specifications. It does not determine the exact particle-size distribution of a sample, the percentage retained on a sieve, or the manufacturing tolerance of a particular screen. Those require a physical sieve analysis and a specified standard.

When to use it

Use the converter when you need to compare a powder specification written as “100 mesh” with a particle size stated in micrometres; when selecting adjacent test sieves for a screening sequence; when translating a vendor's mesh designation into metric units; or when preparing a laboratory worksheet that needs both mesh and opening dimensions.

How to calculate

1. The calculator opens with a complete demonstration: 100 mesh, which corresponds to a nominal opening of 149 µm. The Excel workbook is ready immediately.
2. Choose a value from U.S. mesh number. Results update as soon as the selection changes.
3. Read Nominal opening as the tabulated opening size. Use Millimetres or Inches when another unit is required. The Rule-of-thumb value shows 14,900 divided by mesh and is most useful from roughly 50 to 400 mesh.
4. Review Nearby sieve sizes to see the selected sieve in context, then choose Download Excel to export the current inputs and typed results.
5. Reset clears the demonstration and results. Download Excel is then disabled until a complete valid mesh selection is entered again.

Input guide

U.S. mesh number is required and must be one of the listed conventional sieve designations. Mesh is a count-like designation representing approximately how many openings occur across one linear inch; it is not itself a length. For example, selecting 200 produces a nominal opening of 74 µm. A larger mesh number generally means a smaller opening. A common mistake is to assume that mesh and micron are connected by one exact universal formula. Wire diameter changes across sieve constructions, so standard tables are preferred. The ASTM E11 test-sieve specification describes requirements for wire cloth and sieve construction.

Output guide

Nominal opening is the table value in micrometres (µm). Millimetres is the same opening divided by 1,000. Inches is the same opening divided by 25,400. Openings per inch repeats the selected mesh designation for clarity. Rule-of-thumb value applies the approximate relationship 14,900 ÷ mesh; it is an estimate and may differ from the table, especially for coarse meshes. The header pills repeat the current mesh and nominal opening. In the Nearby sieve sizes table, each row lists a mesh designation and the same nominal opening in three length units.

Worked example

With the startup selection of 100 mesh, the standard table gives 149 µm. Converting units gives 149 ÷ 1,000 = 0.149 mm and 149 ÷ 25,400 = 0.005866... in, displayed as 0.00587 in. The approximate formula gives 14,900 ÷ 100 = 149 µm, so the rule of thumb agrees exactly with this table entry. The exported workbook records 100 as a numeric input and 149, 0.149, and 0.005866... as numeric outputs rather than formatted text.

Learn more

For the measurement context, the NIST guidance on SI length units explains metre-based units, including the micrometre prefix. For laboratory practice, ISO 3310-1 for metal wire cloth test sieves covers technical requirements and testing. These standards are more authoritative than an approximate conversion equation when purchasing or certifying a sieve.