Area of Shapes Calculator
Choose a shape and enter its dimensions to find its area.
Area formulas for common shapes
Square: side². Rectangle: length × width. Triangle: ½ × base × height. Circle: π × radius². Trapezoid: ½ × (base1 + base2) × height. Parallelogram: base × height.
These formulas all measure the two-dimensional space enclosed by the shape, in whatever squared unit your inputs are in (e.g. entering meters gives an area in square meters).
Frequently asked questions
Why is the triangle's area formula ½ × base × height?
A triangle is exactly half of a parallelogram with the same base and height — so its area is half of base × height.
What's the difference between a trapezoid and a parallelogram?
A trapezoid has exactly one pair of parallel sides (the two bases, which can be different lengths); a parallelogram has two pairs of parallel sides of equal length.
Why does the triangle calculator here use base and height instead of three side lengths?
This is the simplest area formula when you know a base and the perpendicular height to it. If you only know the three side lengths, use the dedicated triangle calculator, which uses Heron's formula instead.