01 — Quick referenceCommon mesh sizes in microns
| Mesh | Microns (µm) | Millimeters | Inches |
|---|---|---|---|
| 10 mesh | 2,000 | 2 | 0.0787 |
| 20 mesh | 850 | 0.85 | 0.0335 |
| 30 mesh | 600 | 0.6 | 0.0236 |
| 40 mesh | 425 | 0.425 | 0.0167 |
| 50 mesh | 300 | 0.3 | 0.0118 |
| 60 mesh | 250 | 0.25 | 0.0098 |
| 80 mesh | 180 | 0.18 | 0.0071 |
| 100 mesh | 150 | 0.15 | 0.0059 |
| 120 mesh | 125 | 0.125 | 0.0049 |
| 150 mesh | 106 | 0.106 | 0.0042 |
| 200 mesh | 75 | 0.075 | 0.003 |
| 250 mesh | 63 | 0.063 | 0.0025 |
| 325 mesh | 45 | 0.045 | 0.0018 |
| 400 mesh | 38 | 0.038 | 0.0015 |
| 500 mesh | 25 | 0.025 | 0.001 |
| 800 mesh | ≈ 15.9 | 0.016 | 0.0006 |
Values are ASTM E11 nominal openings (Tyler equivalents for 150 and 250 mesh). Italic ≈ values are estimates for non-standard mesh counts, calculated from the mesh count and an assumed wire diameter (interpolated between ASTM E11 sieves, or extrapolated beyond No. 635). Wire values are ASTM E11 typical wire for standard sizes.
See the full mesh to micron chart →
02 — How it worksHow mesh size converts to microns
Mesh is the number of openings in one linear inch of screen. A 100 mesh screen has 100 openings per inch. Because one inch is 25,400 microns, the distance from the center of one wire to the next (thepitch) is 25,400 ÷ 100 = 254 µm. Part of that distance is taken up by the wire itself, so the actual opening is smaller:
Opening (µm) = 25,400 ÷ mesh − wire diameter (µm)A standard No. 100 test sieve typically uses 0.10 mm (100 µm) wire, so the opening is about 254 − 100 = 154 µm, which is within tolerance of the ASTM E11 nominal value of 150 µm. (Standard sieves are specified by their opening, not by an exact mesh count.) That is why the same mesh count can give different micron values if the wire is thicker or thinner. Use the wire mesh calculator when you know your wire diameter.
Quick rule of thumb
For fine meshes, mesh × microns ≈ 15,000 gives a fast estimate (100 mesh ≈ 150 µm, 200 mesh ≈ 75 µm). It becomes less accurate for coarse screens and non-standard wire, so use the calculator for anything that matters.
ASTM E11 vs. Tyler mesh
The US Standard (ASTM E11) and the older Tyler series share the same openings but label some of them with different numbers. For example, the 106 µm opening is No. 140 in ASTM and 150 mesh in Tyler; the 425 µm opening is No. 40 in ASTM and 35 mesh in Tyler. The sieve size chart lists both side by side.
03 — By sizeMesh size pages
- 20 mesh to micron
- 30 mesh to micron
- 40 mesh to micron
- 50 mesh to micron
- 60 mesh to micron
- 80 mesh to micron
- 100 mesh to micron
- 120 mesh to micron
- 150 mesh to micron
- 200 mesh to micron
- 250 mesh to micron
- 270 mesh to micron
- 325 mesh to micron
- 400 mesh to micron
- 500 mesh to micron
- 800 mesh to micron
04 — FAQFrequently asked questions
How do you convert mesh to microns?
Divide 25,400 (microns per inch) by the mesh number, then subtract the wire diameter in microns: opening (µm) = 25,400 ÷ mesh − wire diameter (µm). For standard test sieves, use the ASTM E11 table instead, because each sieve number has a fixed nominal opening.
What is 100 mesh in microns?
100 mesh = 150 µm (0.150 mm, 0.0059 in) for an ASTM E11 No. 100 sieve. See the 100 mesh page for details.
What is 200 mesh in microns?
200 mesh = 75 µm (0.075 mm). The No. 200 sieve is the standard dividing line between sand and "fines" (silt and clay) in soil testing.
Is a higher mesh number finer or coarser?
Finer. Mesh counts the openings per linear inch, so more openings per inch means each opening is smaller. 400 mesh (38 µm) is much finer than 40 mesh (425 µm).
Why do different mesh to micron charts show different numbers?
Three reasons: (1) some charts use the US ASTM E11 series and others the older Tyler series, which label a few sizes differently (e.g. 35 mesh is 500 µm in ASTM but 425 µm in Tyler); (2) industrial wire cloth with the same mesh count can use thicker or thinner wire, which changes the opening; (3) some charts use the rough rule "mesh × microns ≈ 15,000" instead of real sieve values.
What is the difference between mesh and micron?
Mesh is a count (openings per inch of screen); a micron (µm) is a length, one-thousandth of a millimeter. Micron ratings describe the actual opening size, so they are more precise when comparing screens and filters.