square millimeter to square inch Converter

To convert square millimeter to square inch, multiply the value in square millimeter by 0.00155.

For example, 1 square millimeter = 0.00155 square inch.

In reverse, 1 square inch = 645.16 square millimeter.

To convert square millimeter to square inch, enter your value in square millimeter into the converter above. The tool automatically applies the correct conversion ratio and shows the result in square inch.

This page is useful when you need a fast answer, a quick reference table, or the exact formula for switching between square millimeter and square inch.