GeoCalc
Free geometry calculators for every shape. Instant results, clear formulas, step-by-step explanations.
Quick Answer
Circle area = πr². Triangle area = ½bh. Rectangle area = l×w.
Example: Circle with radius 5 → π × 25 ≈ 78.54 sq units
Popular Calculators
Circle Calculator
Calculate area, circumference, diameter, and sector area from radius.
Rectangle Calculator
Calculate area, perimeter, and diagonal from length and width.
Triangle Calculator
Calculate area (Heron's formula), perimeter, and angles from three side lengths.
Square Calculator
Calculate area, perimeter, and diagonal from side length.
Parallelogram Calculator
Calculate area and perimeter from base, height, and side length.
Trapezoid Calculator
Calculate area and perimeter from parallel sides, height, and legs.
About GeoCalc
GeoCalc provides free, instant geometry calculators with accurate formulas for students, engineers, teachers, and anyone who needs quick geometric calculations.
All calculations are performed in your browser — no data is sent to any server. Results are shown with the formulas used so you can verify and learn.
Frequently Asked Questions
What is geometry?
Geometry is a branch of mathematics that studies the properties, measurements, and relationships of points, lines, angles, surfaces, and solids. It covers 2D shapes (circles, triangles, rectangles) and 3D shapes (spheres, cubes, cylinders).
How do I calculate the area of a circle?
Area of a circle = pi x r², where r is the radius. For example, a circle with radius 5 cm has area = pi x 25 = 78.54 cm². The circumference is 2 x pi x r = 31.42 cm. Use our circle calculator for instant results.
What is the Pythagorean theorem?
The Pythagorean theorem states that in a right triangle, a² + b² = c², where c is the hypotenuse (longest side) and a, b are the other two sides. For example, a triangle with sides 3 and 4 has hypotenuse = sqrt(9 + 16) = 5. Try our Pythagorean theorem calculator.
How do I calculate the volume of a sphere?
Volume of a sphere = (4/3) x pi x r³, where r is the radius. For a sphere with radius 10 cm: V = (4/3) x pi x 1000 = 4,188.79 cm³. Surface area = 4 x pi x r² = 1,256.64 cm². Use our sphere calculator.