Convert Square Thou to Square Millimeters

Convert Square Thou (thou²) to Square Millimeters (mm²) instantly and accurately.

Square Thou (thou²)
Square Millimeters (mm²)

Conversion Formula

mm² = thou² × 0.00064516

About Square Thou

A square thou (thou²), sometimes called a square mil, is the area of a square with sides of one thousandth of an inch (0.0254 mm), equal to approximately 6.452 × 10⁻¹⁰ m². This tiny imperial unit is indispensable in precision engineering, PCB (printed circuit board) design, and manufacturing, where conductor widths, dielectric coating thicknesses, and tight machining tolerances are specified in thou. Wire insulation, thin films, and precision-stamped metal components are commonly described using this unit.

About Square Millimeters

A square millimeter (mm²) is a metric unit of area equal to a square with sides of one millimeter. It is commonly used in precision engineering, electronics, and measuring very small surfaces such as microchips or printed circuit boards. To visualise: a typical pinhead has an area of about 2-3 mm². This unit is essential in microscopy, medical imaging, and manufacturing where tiny, precise measurements are critical.

Quick Reference Table

Square Thou (thou²)Square Millimeters (mm²)
1 thou²0.00064516 mm²
2 thou²0.00129032 mm²
5 thou²0.0032258 mm²
10 thou²0.0064516 mm²
25 thou²0.016129 mm²
50 thou²0.032258 mm²
100 thou²0.064516 mm²

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