# Square Inches to Square Millimeters Conversion

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

## 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 in to sq mm, multiply 10 by 645.16, that makes 6451.6 sq mm is 10 sq in.

1 Square Inch = 645.16 Square Millimeters

## 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.

1 Square Millimeter = 0.0015500031 Square Inch

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. 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.