Screw Size Chart (Gauge to Inches & Metric)

Screw gauge numbers convert to real diameters. This chart maps the common gauges to inches and millimeters.

GaugeMajor dia (in)Major dia (mm)Common lengthsTypical use
#20.0862.21/4–1Small hinges, electronics
#40.1122.83/8–1-1/2Cabinet hardware, toys
#60.1383.51/2–2Light woodworking, fixtures
#80.1644.21/2–3General woodworking, hinges
#100.1904.83/4–4Heavier joints, decking
#120.2165.53/4–4Heavy-duty wood
#140.2426.31–6Structural wood, framing

Gauge numbers do not run consecutively — always refer to the diameter column when matching hardware.

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