⭕ Circle Calculator
Enter the radius to calculate circumference, area, sphere surface area, and sphere volume
📊 Result Chart
❓ FAQ
How to calculate the circumference of a circle?
Circumference = 2πr, where r is the radius and π ≈ 3.14159. For example, a circle with radius 5 cm has circumference ≈ 31.42 cm.
How to calculate the area of a circle?
Area = πr², where r is the radius. For example, a circle with radius 5 cm has area ≈ 78.54 cm².
How to calculate sphere surface area and volume?
Sphere surface area = 4πr², sphere volume = (4/3)πr³. For example, a sphere with radius 5 cm has surface area ≈ 314.16 cm² and volume ≈ 523.60 cm³.
How to convert between diameter and radius?
Diameter = 2 × radius, radius = diameter ÷ 2. This calculator takes radius as input and also displays the diameter in results.