▭ Area Calculator
Calculate the area of common 2D shapes: squares, rectangles, circles, triangles, trapezoids, parallelograms, and ellipses.
Shape & Dimensions
Result
Area Formulas
Rectangle: A = l × w
Circle: A = π r²
Triangle: A = ½ × b × h
Trapezoid: A = ½ × (b₁ + b₂) × h
Parallelogram: A = b × h
Ellipse: A = π × a × b
Worked Example
The calculator loads with a square of side length 5 ft. Using A = s², the area is 5 ft × 5 ft = 25 ft². Switching to a different shape — say a rectangle 8 ft by 5 ft — would instead give A = l × w = 8 × 5 = 40 ft².
Frequently Asked Questions
What units does this calculator use?
You can select any linear unit (ft, m, in, cm) — the result is shown as that unit squared, e.g. ft².
How is a trapezoid's area different from a parallelogram's?
A trapezoid has two parallel sides of different lengths, so its area formula averages the two bases: ½ × (b₁ + b₂) × h. A parallelogram's two pairs of sides are equal, so its area is simply base × height.
What's the difference between a circle and an ellipse formula?
A circle is a special ellipse where both axes are equal (the radius). An ellipse uses two different axis lengths (semi-major and semi-minor).