How to Find Square Inches in a Rectangle

    A unit of measurement is defined as a definite magnitude of a quantity. It is adopted by law and is used as a standard for measurement of the quantities that fall in the same category. For other quantities of a similar category, we can express it as a multiple of the unit of measurement. For example, width is a physical quantity. 

    Measuring something is an act of establishing a target’s weight, width, size, length, capacity, area, volume, or other aspects. It can also be defined as numerical quantitation of the attributes of an object. We can utilize this numerical quantity to compare the attributes of an object with other objects. It has innumerable applications in science, mathematics, and day-to-day activities.

    In simple words, it is a method of determining a number that reveals the amount or size of something. 

    What is Square Inch?

    The unit of area of measurement equal to a square measuring an inch on each side is a square inch. Commonly used symbols for this unit of measurement are sq in, sq inches, inches2, inch2, and in2

    1 square inch is equal to 0.006 94 square feet, 1 square inch is equal to 0.000 771 604 9382 square yards, 1 square inch is equal to 6.4516 square centimeters, and 1 square inch is equal to 0.000 645 16 square meters.

    A square inch is a common unit of measurement in the United States and the United Kingdom.

    This article will discuss ways to determine the square inches / sq in/ inches2 in any two-dimensional area. Typically calculating square inches in any two-dimensional object is a simple process. 

    Determining Square Inches in a Square or Rectangle

    The equation for the measurement of the area of a two-dimensional square or a rectangle is the multiplication of the length and width of the shape. A variety of specific mathematical equations can calculate the area of other shapes like triangles, circles, and more. 

     To begin with, the procedure determines the length of the area that needs to be measured. With squares, all four sides are equal. With rectangles, opposite sides have equal lengths. Measure all sides of the square (all four sides should be equal) or rectangle (length and width) to find a value for length. 

    Since all four of a square’s sides are equal, you only need to measure one side. The “length” for a square will be identical to the “width”. 

    In the case of a rectangle, you need to measure length and width separately. Length and width need to be at a right angle with each other.

    For example, for a rectangular area, the length is 5 inches and the width is 4 inches. Here, the area within your rectangle is 5 × 4 = 20 square inches.

    In the case of a square, if you measure one side of 3 inches, all four sides are the same, just multiply it by itself. It is also known as squaring or taking it to the second power. The area of a square with one side being 3 inches is 3 x 3 = 9 square inches.

    Determining Square Inches in Other Shapes

    Now that we are done with determining the square inches for simpler and straight forward shapes like square and rectangle, it’s time to move on to something comparatively advanced. 


    The formula to calculate the area of a circle is (pi. r2). Here, ‘r’ represents the radius of the circle. The radius of a circle is the distance from the center of the circle to its edge in inches. After measuring the radius, you may replace ‘r’ with the value and multiply it by itself. The value of Pi = 3.1415926… 

    For example, if the radius of a circle is 3 inches. The area of that circle will be (3.14 x 9) square inches.


    The formula for calculating the area of a triangle is ½ b x h. Here, ‘b’ represents the base of the triangle. The base is any chosen side of the triangle. ‘h’ represents the height of the triangle. Height is the distance from the base side to the opposite corner. We can use any of the three sides as the base of a triangle. The only condition is that height is calculated only by measuring the distance between the chosen base and the opposite corner measured at the right angle. 

    For example, the base side length is 4 inches, and the corresponding height is 2 inches, the area of the triangle will be 4 square inches.


    The parallelogram is somewhat similar to a rectangle with two opposite sides being equal in length. The noticeable difference between parallelogram and rectangle is that the corners don’t necessarily create a right angle, i.e. 90 degrees. The formula for determining the area of a parallelogram is B x H. ‘B’ represents the base of this shape. It can be any one side of the parallelogram. ‘H’ represents the height of this shape. It can be calculated by measuring the distance between the base and the opposite corner measured at the right angle.

    For example, the length of the parallelogram’s base is 4 inches, and the corresponding height is 5 inches, then the area will be 20 inches.


    A trapezoid is another four-sided shape. In this shape, one pair of sides is parallel to each other, and one pair of sides is not parallel to each other. The equation to calculate a Trapezoid area is 1/2 x h x (B + b). Three measurements are required to calculate the area of this four-sided shape. 

    ‘B’ is the length of the longer parallel side. ‘b’ is the length of the shorter parallel side. And ‘h’ is the height of the trapezoid. Height is measured as the distance between the two parallel sides, measured at ninety degrees. The formula requires us to add the length of two parallel sides and multiply it with the corresponding height and then divide it by two.

    For example, the length of the long parallel side of a trapezoid is 8 inches. The length of the short parallel side of a trapezoid is 6 inches. Height is 4 inches. The area will be 28 sq inches.

    Regular Hexagon

    A regular hexagon is a six-sided shape with equal lengths and angles. The formula for determining the area of a regular hexagon is ½ x P x a. ‘P’ is the perimeter of the hexagon. Perimeter is calculated by multiplying six to the length of any one side of a regular hexagon. So if a side of the hexagon is 2 inches, the perimeter will be 12 inches. ‘a’ is the apothem. Apothem is the distance from the center of the hexagon to the midpoint of any side of the shape. 

    For example, P’s value for a regular hexagon is 12 inches, and a is 5 inches, then the area of such shape will be 30 sq. inches. 

    Regular Octagon

    A regular octagon is an eight-sided shape with equal sides and angles. The formula for calculating the area of a regular octagon is 2a² × (1 + √2). Here ‘a’ is the length of any side of an octagon. 

    For example, if the length of a side of a regular octagon is 2 inches, then the area of such an octagon will be 9.6 square inches.

    Unit Conversion

    In case the measurements are provided in some other unit, then you may use the following chart to convert them into inches.

    1 millimeter = 0.0394 inches

    1 centimeter = 0.3937 inches

    1 meter = 39.3701 inches

    1 foot = 12 inches

    1 yard = 36 inches

    Measurement formulas and examples not only help in solving a numerical question but also helps in clarifying the concepts. A lot of mathematics and physics problems can be simply solved by using formulas. The application of formulas in examples further simplifies the topic for a student. If a student struggles to grasp some of the fundamental yet complicated lessons, then an experienced teacher might be helpful. CueMath is a website that provides personalized tuition and a learning path to each of its students. So that your kid does not get lost in the crowd, and gets required attention from his/ her teacher. It is especially great for kids who hesitate to ask questions or feel that they are running behind from the rest of the class. You may book a free trial class at CueMath and experience the difference of personalized education. 


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