Area Calculator
Calculate the area of a rectangle, circle, triangle, trapezoid, ellipse, and more — with formulas explained.
Our free area calculator works out the area of the most common shapes instantly. Select your shape, enter the dimensions, and the result updates as you type.
How to calculate the area of a rectangle
Area = length × width
For example, a rectangle 10 m long and 5 m wide has an area of 50 m².
How to calculate the area of a circle
Area = π × radius²
For example, a circle with a radius of 7 m has an area of π × 49 ≈ 153.94 m².
How to calculate the area of a triangle
Area = ½ × base × height
For example, a triangle with a base of 10 m and a height of 6 m has an area of ½ × 10 × 6 = 30 m².
How to calculate the area of a trapezoid
Area = ½ × (base a + base b) × height
Add the two parallel sides, multiply by the height, then divide by 2.
How to calculate the area of an ellipse
Area = π × a × b
Where a and b are the two semi-axes (half the width and half the height of the ellipse).
How to calculate the area of a parallelogram
Area = base × height
The height is the perpendicular distance between the two parallel bases, not the slant side length.