Square Millimeter to Square Inch

1 Square Inch


645.16 Square Millimeters

Square Millimeter to Square Inch (How many square millimeters in a square inch?)

It is a conversion calculator that is used to convert the area in square millimeter (mm2) to the area in the square inch (in2). The first step when you are using the converter is to enter the value in Square millimeters in the blank text field. The "Convert" button is used to execute the conversions from Square millimeters to square inches. Click this button to get the result in square inches.

The same procedure can always be repeated when you have new values in square millimeters.  It gives quick and accurate results depending on the input values entered in the text field.


Convert 90 square millimeters to square inches.


First, enter the value in square millimeters (90) in the blank text field. Click the ‘convert' button to initiate the conversion from square millimeters to square inches. The result in square inches will be displayed as;

= 0.139500279 square inches

Square Inches to Square Millimeters Conversion

Enter a value that you want to convert into sq. millimeters and click on the "convert" button.

How many square inches in a square millimeter?

The area units' conversion factor of the square millimeter to square inches is 0.00155. If you want to determine the number of square inches in a square millimeter, you will multiply the value in square millimeter by the conversion factor.

1 square millimeter = 0.00155 square inches

This implies that there are 0.00155 square inches in one square millimeter.

For example; how many square inches are in 90 square millimeters?

Using the formula for conversion, we will multiply this value (90 mm2) by the conversion factor to determine the result in square inches.


= 90 x 0.00155

= 0.139500279 square inches.

Therefore, it means that there are 0.139500279 square inches in 90 square millimeters.

The Square millimeter to square inches conversion calculator uses the conversion factor in its formula when performing conversions from square millimeter to square inches. This allows the converter to give quick and accurate results with a single click.

You can also use the Square millimeter to the square inches conversion table to determine the conversions of common values from square millimeters to square inches.


A square millimeter is a derived metric system international (SI) unit of area measurement. It is abbreviated as (mm2) and defined as the unit of area with each of the sides equal to one millimeter.

A Square inch is a US customary and an imperial area unit of measurement. One square inch is equivalent to 6.4516 square centimeters and 0.00064516 square meters. One square foot is equal to 144 square inches. It is a popular unit of measurement in the United States as well as the United Kingdom.