Circle & Sphere Calculator (Pi)
Instantly calculate the area, circumference, and volume of circles and spheres using Pi (π). Free, accurate geometry tool for students, engineers, and professionals.
Calculate With Pi (π)
Enter the radius of your circle or sphere to instantly generate precise measurements for area, circumference, volume, and surface area using the mathematical constant Pi.
Measurement Details
Enter the radius to calculate all related geometric properties
Geometric Evaluation
Calculated properties using Pi (π)
Pi (π) Formulas
Standard geometric formulas utilising Pi to help you understand the underlying mathematics of circles and spheres.
| Shape | Property | Formula | Value (r = 5) |
|---|---|---|---|
| Circle | Circumference | C = 2 × π × r | 31.4159 |
| Circle | Area | A = π × r² | 78.5398 |
| Sphere | Surface Area | SA = 4 × π × r² | 314.1593 |
| Sphere | Volume | V = (4/3) × π × r³ | 523.5988 |
Pi & Geometry FAQ
Everything you need to know about Pi, circles, spheres, and geometric calculations.
Pi (π) is a mathematical constant representing the ratio of a circle’s circumference to its diameter. It is an irrational number, approximately equal to 3.14159, and its decimal representation never ends or repeats.
The area of a circle is calculated using the formula A = π × r², where ‘r’ is the radius of the circle (the distance from the centre to the edge). Multiply Pi by the radius squared to get the area.
The volume of a sphere is calculated using the formula V = (4/3) × π × r³, where ‘r’ is the radius of the sphere. This formula determines the total three-dimensional space enclosed by the sphere.
Yes. The radius is exactly half of the diameter (r = d/2). You can either divide your diameter by 2 before using this calculator, or use the alternative formulas: Area = (π × d²) / 4 and Circumference = π × d.