Circle Properties Calculator
Calculate circle properties from radius: area and circumference. Area = π × r²; Circumference = 2π × r.
Formula
Area = π × r²; Circumference = 2π × r
- Radius: distance from center to edge
- Diameter = 2 × radius
- Circumference (perimeter) = 2πr
- Area = πr²
Example
Inputs
- Radius: 5
Radius 5: Diameter = 10, Circumference ≈ 31.42, Area ≈ 78.54 square units.
Frequently asked questions
What's the relationship between radius and diameter?
Diameter = 2 × radius. Radius is half the diameter.
What's the difference between circumference and area?
Circumference is the perimeter (distance around). Area is the space inside.