What Is US Standard Mesh?

US Standard Mesh is the sieve numbering system defined by ASTM E11 that designates woven wire screen cloth by the number of openings per linear inch, serving as the primary specification system for vibratory screening and particle size classification in North America. When you order a replacement screen by mesh number — 20 mesh, 60 mesh, 200 mesh — you are using the US Standard Mesh system. The number represents how many square openings fit in one linear inch of cloth, measured from center-of-wire to center-of-wire.

The US Standard Mesh series is built on a fourth-root-of-two geometric progression, meaning each standard sieve size has an opening approximately 1.189 times larger than the next finer size. This progression creates the familiar series: 4, 5, 6, 7, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 100, 120, 140, 170, 200, 230, 270, 325, 400, 450, and 500 mesh. The system is functionally equivalent to the older Tyler Mesh standard at most common sizes and corresponds to metric openings defined in ISO 3310.

US Standard Mesh Quick Reference

Why This Matters in Vibratory Screening

US Standard Mesh is the universal language of screen specification in North American vibratory screening. Every aspect of screen selection, quality control, and process documentation revolves around mesh designations.

• Screen ordering — Replacement screens for Sweco, Kason, Midwestern Industries, Cleveland Vibratory, Russell Finex, and ScreenerKing separators are specified by US Standard Mesh. Using the correct mesh designation ensures the correct opening size for your separation.
• Quality specifications — Product specifications and certificates of analysis define particle size limits using mesh designations: "100% through 20 mesh, less than 5% through 100 mesh" is a typical spec that only makes sense within the US Standard Mesh system.
• Process control — Sieve analysis results are reported using US Standard Mesh designations, allowing direct correlation between lab test results and production screen selection.
• Cross-system compatibility — Understanding how US Standard Mesh relates to Tyler Mesh and ISO 3310 metric designations prevents costly specification errors, especially when working with legacy equipment or international customers.

Related Glossary Terms

• ASTM E11 — The standard that defines the US Standard Mesh series
• Tyler Mesh — The historical mesh sizing standard
• ISO 3310 — The international sieve standard using metric designations
• Mesh Size — General explanation of mesh count and opening size
• Micron — The metric unit for screen opening size
• Sieve Analysis — Lab test that uses US Standard Mesh sieves

US Standard Mesh FAQs

What is US Standard Mesh?

US Standard Mesh is the sieve numbering system defined by ASTM E11 that designates screen openings by counting the number of openings per linear inch. A 100 mesh screen has 100 openings per linear inch, resulting in a 149-micron nominal opening. It is the dominant screen specification system for vibratory screening in North America.

How does US Standard Mesh relate to particle size?

US Standard Mesh has an inverse relationship with particle size — higher mesh numbers mean smaller openings. A 20 mesh screen has 841-micron openings (coarse), while a 325 mesh screen has 44-micron openings (very fine). The mesh number alone does not determine the exact opening size because wire diameter also plays a role, which is why ASTM E11 specifies both mesh count and wire diameter.

Can I convert between US Standard Mesh and metric sizes?

Yes. Each US Standard Mesh number corresponds to a specific nominal opening in microns and millimeters as defined by ASTM E11. Use the ScreenerKing mesh-to-micron conversion calculator or the mesh size conversion chart for precise values. ISO 3310 uses the metric openings directly rather than mesh numbers.