Utility

Mesh Size Converter

Convert between US mesh number, microns, millimeters, and inches for ceramic sieves, grog sizes, and material particle sizing.

Updated May 2026

Value

From Unit

Common Ceramic Mesh Reference

#20 = 850 µm #40 = 425 µm #80 = 180 µm #100 = 150 µm #200 = 75 µm #325 = 45 µm #400 = 38 µm

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Mesh, Microns, and Ceramics

Sieve mesh numbers indicate how many wires cross one linear inch. A higher mesh number means finer openings. This is the opposite of grit numbers (sandpaper), where higher = finer too — but the scale is completely different.

ASTM E11 Standard Mesh Reference

US Mesh	Microns (µm)	mm	Ceramic Use
16	1180	1.18	Coarse grog (hand-building)
40	425	0.425	Medium grog
80	180	0.180	Fine grog, throwing bodies
100	150	0.150	Glaze material sieving
200	75	0.075	Standard glaze screening
325	45	0.045	Fine material QC testing
400	38	0.038	Analytical screening

The Approximation Formula

Microns ≈ 25,400 / US Mesh number (Tyler series)

Example: Mesh 200 = 25,400 / 200 = 127 µm (approx.)
ASTM standard actual = 75 µm (much finer — use the table)

The formula is only an approximation. For standard mesh numbers, always use the ASTM table values.

Grog Selection Guide

Coarse sculpture / raku: 16–30 mesh (600–1180 µm) for maximum texture and open body
Handbuilding slabs: 30–50 mesh (300–600 µm) balances texture and workability
Wheel throwing: 80–120 mesh (125–180 µm) for smooth walls
Porcelain: 120–200 mesh or no grog

lightbulb Quick Tips

check_circle Pass all glaze materials through 80–100 mesh before weighing. Lumps and undissolved particles cause glaze speckling and uneven surface in the finished piece.
check_circle When buying grog, note whether the supplier uses US mesh or European metric sizing — they are not the same scale. Always ask for the micron size to be sure.
check_circle A 200-mesh glaze screen is the standard for studio use. Finer sieves (325 mesh) are useful for ash glazes or materials with coarse particles that can cause crawling.

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Frequently Asked Questions

What mesh size grog should I use for handbuilding? expand_more

Coarse handbuilding clays typically use 16–40 mesh grog (425–1180 µm). This open texture prevents cracking in thick slabs. Fine throwing bodies use 80–100 mesh grog (150–180 µm) for smoothness on the wheel.

What is 200 mesh in microns? expand_more

200 mesh = 75 µm (0.075mm). This is the standard sieve for passing glaze materials in studio ceramics. Most glaze base materials should pass through 200 mesh for good suspension and smooth application.

What sieve do I use for testing fine materials like volcanic ash? expand_more

For fine material analysis, ceramicists use 325 mesh (45 µm) as a standard quality check. The percentage that passes 325 mesh indicates how fine a material is. Materials finer than 325 mesh require specialised analytical sieves.

Why does the mesh-to-micron formula give different results than the table? expand_more

The formula "microns ≈ 25400 / mesh" is an approximation. The ASTM E11 standard specifies precise wire diameters and aperture tolerances for each mesh size. For standard mesh numbers (10, 20, 100, 200, 325), always use the table values rather than the formula.