Circumference Calculator

Calculate the circumference and area of a circle using either the radius or diameter. Simply enter your measurement, select the type, and get instant results.

How to Use the Circumference Calculator

Follow these simple steps to calculate the circumference and area of a circle:

1. Select whether you want to enter the radius or diameter of the circle
2. Enter the measurement value in the input field
3. Click the Calculate button to see the results
4. View both the circumference and area of the circle instantly

Circle Formulas

This calculator uses the following mathematical formulas:

• Circumference from Radius: C = 2πr
• Circumference from Diameter: C = πd
• Area from Radius: A = πr²
• Area from Diameter: A = π(d/2)²

About Circle Calculations

A circle is a fundamental geometric shape where all points are equidistant from the center. The circumference is the distance around the circle, while the area represents the space enclosed within it. Understanding these measurements is essential for various applications in mathematics, engineering, construction, and everyday problem-solving.

The value of π (pi) used in these calculations is approximately 3.14159, which represents the ratio of a circle's circumference to its diameter.