Square inches to square millimeters conversion table shows the most common values for your quick reference. Also, you may use the converter below to convert any other values.
1 Sq. Inch = 645.16 Sq. Millimeters
Sq. millimeter is an area unit in metric system and used rarely. Commonly spelled as
"square millimetre" in many countries. The abbreviations are "mm2" or "sq mm".
Sq. inch is an imperial, US customary area unit. The abbreviations are "sq in" and "in2".
For other area unit conversions, please go to Area Conversion