By Melissa Kelly
Updated Aug 30, 2022

Area measures the size of a specific region and is expressed in square units such as square meters or square kilometers. Calculating the area of a space is essential for everyday tasks—from estimating the amount of carpet needed for a bedroom to planning a landscaping project. While the principle remains the same—measuring how much surface an object covers—the formulas vary depending on the shape.

Area of a Rectangle

Step 1

Measure the length of the rectangle.

Step 2

Measure the width of the rectangle.

Step 3

Multiply the length by the width. Ensure both measurements use the same unit; the result will be expressed in square units.

Area of a Circle

Step 1

Determine the radius of the circle.

Step 2

Square the radius by multiplying it by itself. This gives you the radius squared.

Step 3

Multiply the squared radius by π (π ≈ 3.1415927). The product is the area in square units.

Area of a Triangle

Step 1

Measure the length of the base of the triangle.

Step 2

Measure the height (the perpendicular distance from the base to the opposite vertex).

Step 3

Multiply the base by the height. Use consistent units.

Step 4

Divide the result by two. The quotient is the area in square units.

Things Needed

• Calculator
• Tape measure

TL;DR (Too Long; Didn’t Read)

When measuring a shape that isn’t a perfect square, break it into smaller sections, calculate each area, and sum them for the total.