# Square Inches to Square Millimeters Conversion

Round:
Enter Square Inch
Enter Square Millimeter
Calculate Area
in
×
in

To convert square inches to square millimeters (in2 to mm2) or to convert square millimeters to square inches (mm2 to in2), you may use the converter above. To calculate the area in square inches and convert into square millimeters at the same time, you may enter the dimensions in inches.

Below, you will find information of how to find out how many square millimeters there are in "x" square inches, including the formulas and example conversions.

## How to convert square inches to square millimeters?

1 Square inch is equal to 645.16 square millimeters. To convert square inches to square millimeters, multiply the square inch value by 645.16.

For example, to convert 10 sq inches to sq mm, multiply 10 by 645.16, that makes 6451.6 sq mm is 10 sq inches.

square inches to square mm formula

square mm = square inch * 645.16

## How to convert square millimeters to square inches?

1 Square millimeter is equal to 0.0015500031 square inch. To convert square mm to square inches, multiply the square mm value by 0.0015500031 or divide by 645.16.

square mm to square inches formula

square inch = square mm * 0.0015500031

square inch = square mm / 645.16

What is a Square Inch?

Square inch is an imperial and United States Customary area unit. 1 sq in = 645.16 sq mm. The symbol is "in²".

What is a Square Millimeter?

Square millimeter (millimetre) is a metric system area unit. 1 sq mm = 0.0015500031 sq in. The symbol is "mm²".

Please visit all area units conversion to convert all area units.

Create Conversion Table
Click "Create Table". Enter a "Start" value (5, 100 etc). Select an "Increment" value (0.01, 5 etc) and select "Accuracy" to round the result.