Calculate area and perimeter of circles, rectangles, triangles
Built & maintained by Pappu Venkata Subbi Reddy, founder of Clacify
Clacify's Area Calculator computes the area and perimeter for common 2D shapes: circle (πr²), rectangle (l×w), square (s²), triangle (½×b×h), parallelogram (b×h), trapezoid, and ellipse. Enter the dimensions and get instant results with the formula used. Useful for construction planning, garden layout, fabric cutting, tiling, and geometry homework.
Area of a circle = π × r², where r is the radius. If you have the diameter, r = diameter ÷ 2. Example: A circle with radius 7 cm has area = π × 7² = 3.14159 × 49 = 153.94 cm². Circumference = 2πr = 2 × 3.14159 × 7 = 43.98 cm.
Area of a triangle = ½ × base × height. For a right triangle: ½ × leg1 × leg2. Using three sides (Heron's formula): Area = √[s(s−a)(s−b)(s−c)] where s = (a+b+c)/2 (semi-perimeter). Example: triangle with base 10 cm and height 6 cm: Area = ½ × 10 × 6 = 30 cm².