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Area Calculator

Calculate the area of common 2D shapes — rectangle, circle, triangle, trapezoid, ellipse, and parallelogram.

Rectangle: Length | Circle: Radius | Triangle: Base | Trapezoid: Base 1 | Ellipse: Semi-axis a | Parallelogram: Base
Rectangle: Width | Triangle: Height | Trapezoid: Base 2 | Ellipse: Semi-axis b | Parallelogram: Height
Only used for Trapezoid (the perpendicular height between the two bases)

Results

Area50.0,000 sq units

📖What is it?

Area is the amount of 2D space enclosed by a shape, measured in square units. Formulas: Rectangle = l × w; Circle = πr²; Triangle = ½ × base × height; Trapezoid = ½ × (b₁ + b₂) × h; Ellipse = π × a × b; Parallelogram = base × height.

🎯How to use

Select your shape, then fill in the required dimensions. Dimension 1 and 2 serve double duty depending on the shape (see help text for each field). Dimension 3 is only used for the Trapezoid (the perpendicular height). Results are in square units — if you measured in metres, the area is in m².

💡Example scenario

Flooring a rectangular room: 5 m × 4 m = 20 m². Painting a circular feature wall with radius 1.5 m: π × 1.5² ≈ 7.07 m². A triangular garden bed with base 3 m and height 2 m: ½ × 3 × 2 = 3 m².

🏆Pro tip

Always square your units. If dimensions are in centimetres, the area is in cm² (divide by 10,000 for m²). For irregular shapes, break them into simpler components and sum the areas. Heron's formula can compute triangle area from three side lengths when the height is unknown.