Mesh to Micron Converter
Sieve mesh number to opening size lookup using the official ASTM E11 and Tyler standard tables. Forward and reverse conversion, full charts, no formulas pretending to be exact.
| Mesh | Opening (micron) | Opening (mm) | Opening (inch) |
|---|
Honesty note. A mesh number is a label, not a measurement. These are the nominal openings published by each standard; real sieves carry manufacturing tolerances and wire-diameter specs, so a certified sieve's measured opening differs slightly. Values are rounded to the nearest micron.
Worked examples
1. ASTM No. 200 sieve: nominal opening 75 micron (0.075 mm). This is the classic sand to silt boundary in soil testing.
2. ASTM No. 100 sieve: nominal opening 150 micron (0.150 mm).
3. Tyler 100 mesh: nominal opening 147 micron, not 150. Same mesh number, different standard, different opening.
4. Reverse: 500 micron maps to the nearest ASTM sieve, No. 35 (exactly 500 micron).
Boundary. This tool converts sieve mesh numbers to openings. If you need pure length-unit conversion (for example micron to millimeter or inch as units), use a length converter instead. A dedicated micron to mil conversion tool (pipeline #955) covers micron as a length unit.
Frequently asked questions
What does a mesh number mean?
A mesh number is the count of openings per linear inch of a sieve screen. Higher mesh numbers mean more, smaller openings. For example, a No. 100 sieve has 100 openings per inch.
Is mesh to micron an exact conversion?
No. A mesh number is only a label; the actual opening size depends on the wire diameter and the standard used (ASTM E11 or Tyler). Always look up the nominal opening from the official table instead of calculating it.
What is the difference between ASTM E11 and Tyler sieves?
ASTM E11 is the modern US standard that defines nominal openings such as No. 100 = 150 microns. The Tyler series is older, based on a 74-micron opening for 200 mesh with a square-root-of-2 progression, so Tyler 100 = 147 microns. Values are close but not identical.
Can I use the formula 14900 divided by mesh?
Only as a rough estimate. It gives 74.5 microns for mesh 200 (close to the real 75), but 596 microns for mesh 25 while ASTM E11 says 710 microns, an error of about 16 percent. For lab or quality work, use the standard table.
Why do two charts sometimes disagree by 1 micron?
Fine sieve openings are rounded differently by different publishers, and the underlying inch values are themselves rounded. Treat the last micron as approximate; certified sieves list their own measured openings with tolerances.
How does the reverse micron to mesh lookup work?
The tool finds the standard sieve whose nominal opening is closest to your value, comparing relative (logarithmic) distance so fine and coarse sizes are treated fairly. It also shows the next coarser and finer sieves for context.
Which standard should I use, ASTM or Tyler?
Use ASTM E11 for modern lab work in the United States and for any new sieve purchases. Use Tyler only when you are reading old specifications, mining and metallurgy references, or equipment rated in Tyler mesh.
What is ISO 3310 and how does it relate?
ISO 3310 is the international test sieve standard. Its nominal openings are harmonized with ASTM E11 for most sizes (for example both list 75 microns for the 200 designation), but designations and tolerances should be checked per standard within one test.
What are the most common sieve sizes?
Common ASTM E11 sizes are No. 4 (4750 microns), No. 10 (2000), No. 40 (425), No. 100 (150), No. 200 (75), and No. 325 (45). The No. 200 sieve at 75 microns is the classic boundary between sand and silt.
Do sieves have tolerances?
Yes. ASTM E11 specifies allowable variation for the average opening, the maximum individual opening, and the wire diameter. A certified sieve ships with measured values and a compliance certificate, which is why nominal table values are approximate.
What is the difference between mesh and micron as a unit?
Mesh is a sieve label (openings per inch), while a micron (micrometer) is a unit of length equal to one millionth of a meter. This tool converts the label to the length; for pure length conversions like micron to mil, use a length unit converter.
Can I interpolate between two mesh numbers?
Interpolation is not meaningful because mesh numbers are labels, not a continuous scale, and the opening depends on wire diameter. If your size is not in the table, use the reverse lookup to find the nearest standard sieve.
What sieve is finer than 400 mesh?
ASTM E11 continues to No. 450 (32 microns), No. 500 (25 microns), and No. 635 (20 microns). Below about 20 microns, woven wire is replaced by electroformed or air-jet sieves, which use different standards.
Why is wire diameter important?
Two sieves with the same mesh number but different wire diameters have different opening sizes, since opening equals pitch minus wire diameter. Standards fix both the opening and the allowed wire diameter so results are comparable between labs.
How do I pick a sieve stack for particle analysis?
A common choice is a square-root-of-2 progression, where each sieve opening is about 1.414 times the next, giving evenly spaced points on a log scale. Keep all sieves in the stack under one standard, either ASTM E11 or Tyler, never mixed.
Where does this table come from?
The ASTM E11 values are the published nominal openings of the ASTM E11 standard, cross-checked against an ISO 3310 and ASTM E11 calibration tolerance table. The Tyler values follow the Tyler Standard Screen 1910 series, rounded to the nearest micron.
Free tool by NRTechStudio