# Square Inches to Square Millimeters Converter

Round:
Square Inches:
Square Millimeters:

The square inches to square millimeters converter is a simple tool to convert from square inches to square millimeters and vice versa. It works by taking the input value in square inches and applying the conversion factor of 645.16 square millimeters per square inch. The converter calculates the equivalent area in square millimeters and displays the result.

Below, you will find information on how many square millimeters are in a square inch and how to accurately convert square inches to square millimeters and vice versa.

## 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 square inches to square millimeters, multiply 645.16 by 10, that makes 6451.6 square millimeters equal to 10 square inches.

square inches to square millimeters conversion formula:

square millimeters = 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 millimeters to square inches, multiply the square millimeters value by 0.0015500031 or divide by 645.16.

square millimeters to square inches conversion formula:

square inch = square millimeters * 0.0015500031

square inch = square millimeters / 645.16

What is a Square Inch?

Square inch is an imperial and United States Customary area unit. 1 Square Inch = 645.16 Square Millimeters. The symbol is "in²".

What is a Square Millimeter?

Square millimeter is a metric system area unit. 1 Square Millimeter = 0.0015500031 Square Inch. 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.