Circle Calculator
Calculate the radius, diameter, circumference, and area of a circle. Enter any one value and calculate the remaining values.
Calculate Circle Measurements
Enter any one known value below.
What Is a Circle?
A circle is a simple closed shape in which every point on the circle is the same distance from its center. This distance is called the radius.
Parts of a Circle
- Center: The point at the center of the circle.
- Radius: The distance from the center to any point on the circle.
- Diameter: The distance across the circle through its center.
- Circumference: The distance around the circle.
Circle Formulas
The Constant π
Pi (π) is a mathematical constant used in circle calculations. Its approximate value is 3.14159.
Frequently Asked Questions
How do I calculate the diameter of a circle?
Multiply the radius by 2. Diameter = 2 × Radius.
How do I calculate the circumference?
Multiply 2 by π and by the radius. Circumference = 2 × π × Radius.
How do I calculate the area of a circle?
Multiply π by the radius squared. Area = π × Radius².
Can I enter any circle measurement?
Yes. Enter the radius, diameter, circumference, or area. The calculator will calculate the remaining measurements.
Disclaimer
This calculator is provided for general mathematical and educational purposes. While we aim to provide accurate results, SmartMyTools does not guarantee that the results are suitable for professional or specialized applications.