Circle Calculator
Use this calculator to find the properties of a circle including area, circumference, diameter and radius. Enter one value and our calculator will determine all other properties instantly.
Select what you know:
What is a Circle?
A circle is a perfectly round shape where all points on the edge are the same distance from the center point. This distance is called the radius (r). The circle is one of the most fundamental shapes in geometry and has many important properties and applications.
The key properties of a circle include its radius (r), diameter (d), circumference (C), and area (A). These properties are all related by simple mathematical formulas.
Circle Formulas
The following formulas define the relationships between the different properties of a circle:
Area Formula:
A = πr²
Circumference Formula:
C = 2πr
Diameter Formula:
d = 2r
In these formulas, π (pi) is a mathematical constant approximately equal to 3.14159. It represents the ratio of a circle's circumference to its diameter and is the same for all circles.
How to Use the Circle Calculator
- Select which circle property you know (radius, diameter, circumference, or area).
- Enter the value for that property.
- Click the 'Calculate' button.
- View the calculated values for all other properties along with the step-by-step calculation.
Applications of Circle Calculations
Circle calculations have numerous practical applications in various fields:
- Engineering: Designing circular components, pipes, wheels, and gears.
- Architecture: Planning circular structures and spaces.
- Physics: Analyzing rotational motion and orbital paths.
- Everyday life: Calculating areas of circular objects, such as pizza sizes, round tables, or garden plots.