What Is Mesh Size? Definition, Conversion Chart & Role in Vibratory Screening

Mesh size is the number of openings per linear inch in a woven wire screen, counted from the center of one wire to a point exactly one inch away. It is the primary specification used to select screen cloth for vibratory screeners and separators across every industry from food processing to mining. A 100 mesh screen, for example, has 100 openings in each linear inch of cloth.

Mesh size follows an inverse relationship with particle size: the higher the mesh number, the smaller the openings and the finer the material that can pass through. A 4 mesh screen has large openings suitable for coarse gravel or pellets, while a 500 mesh screen captures particles barely visible to the naked eye. In North America, mesh size is defined by ASTM E11 (US Standard Sieve Series). The Tyler Mesh series, an older but still referenced standard, uses a nearly identical numbering system. Both standards are used interchangeably on most vibratory screening equipment manufactured by Sweco, Kason, Midwestern Industries, Cleveland Vibratory, and other OEMs.

Mesh-to-Micron Conversion Table

The table below lists the most common mesh sizes used in vibratory screening, with their corresponding opening in microns, millimeters, and inches. These values are based on ASTM E11 standard wire diameters.

For an interactive tool that converts mesh to microns and back, visit the ScreenerKing Mesh-to-Micron Conversion Calculator. For a complete printable reference, see our Mesh Size Conversion Chart.

Why Mesh Size Matters in Vibratory Screening

Mesh size is the single most important specification when ordering a replacement screen or configuring a vibratory screener. Selecting the wrong mesh size means your screener either passes material that should be rejected (mesh too coarse) or blocks material that should pass through (mesh too fine). Either error leads to off-spec product, wasted material, or downstream process failures.

• Product quality control — Mesh size determines the maximum particle size in your finished product. In food, pharmaceutical, and cosmetic applications, this directly affects texture, dissolution rate, and consumer experience.
• Throughput and capacity — Finer mesh sizes have lower open area percentages, which reduces throughput. Choosing the coarsest mesh that still meets your specification maximizes production rates.
• Screen longevity — Finer mesh uses thinner wire diameters, which wear faster under abrasive conditions. Balancing mesh size against screen life is a key operational decision.
• Blinding risk — Certain mesh sizes are prone to blinding when processing near-size particles. Understanding the relationship between your particle size distribution and mesh selection helps avoid costly downtime.

How Mesh Size Relates to Vibratory Screening

Every vibratory screener — whether manufactured by ScreenerKing, Sweco, Kason, Midwestern Industries, or Russell Finex — relies on woven wire screens specified by mesh size. The mesh size determines the aperture (opening size), which defines the cut point between oversize and undersize material.

In a multi-deck vibratory screener, the top deck uses a coarser mesh to remove large contaminants or oversize particles, while lower decks use progressively finer mesh to grade material into multiple fractions. For example, a three-deck separator might use 20 mesh on top, 60 mesh in the middle, and 200 mesh on the bottom to produce four distinct product streams from a single feed.

When the mesh number moves above 200, screening efficiency becomes increasingly difficult to maintain without de-blinding aids such as ball trays, ultrasonic systems, or clean rings. This is because fine mesh screens have very small openings that clog more readily with near-size particles, moisture, or static charge.

Related Glossary Terms

• Micron — The metric unit used alongside mesh to describe screen openings
• Aperture — The actual opening size in a woven wire screen
• Wire Diameter — The thickness of screen wire, which determines the opening size for a given mesh count
• Open Area Percentage — The proportion of the screen that is open space
• Blinding — Clogging of screen openings, especially common at certain mesh ranges
• Screening Efficiency — The percentage of undersize material that passes through the screen

Mesh Size FAQs

What does mesh size mean on a vibratory screen?

Mesh size indicates the number of openings per linear inch in the woven wire screen cloth. A 100 mesh screen has 100 openings per linear inch. Higher mesh numbers mean finer screens with smaller openings, while lower mesh numbers mean coarser screens with larger openings.

How do I convert mesh size to microns?

Mesh size and microns have an inverse relationship — as mesh number increases, the micron opening decreases. For example, 20 mesh equals approximately 841 microns, 100 mesh equals 149 microns, and 325 mesh equals 44 microns. Use the mesh-to-micron conversion calculator for precise values, as the exact micron opening depends on wire diameter.

What is the difference between US Standard mesh and Tyler mesh?

US Standard mesh (ASTM E11) and Tyler mesh are two parallel systems for designating screen openings. Both count openings per linear inch, but they historically used slightly different wire diameters, which affected the actual opening size. Today, ASTM E11 is the dominant standard in North America. At most common sizes the two systems are identical or nearly so, but some Tyler designations (like 150 mesh Tyler) do not have an exact US Standard equivalent.

What mesh sizes are most common in vibratory screening?

The most commonly used mesh sizes in vibratory screening range from 4 mesh (4,760 microns) for coarse scalping to 500 mesh (25 microns) for ultra-fine separation. The 20 to 200 mesh range covers the majority of industrial vibratory screening applications across food processing, pharmaceuticals, chemical, plastics, and minerals industries.

Does a higher mesh number mean a finer screen?

Yes. A higher mesh number means more openings per inch, which requires smaller openings and finer wire. A 400 mesh screen has much smaller openings (37 microns) than a 10 mesh screen (2,000 microns). This inverse relationship is why fine screening applications use high mesh counts.