Circle Calculator

Radius:
Diameter:
Circumference:
Area:
Decimal places:
Circle Diagram
Radius Diameter Circumference Area indicator Circle Properties Radius (r): 0.00 Diameter (d = 2r): 0.00 Circumference (C = 2πr): 0.00 Area (A = πr²): 0.00 • d = 2r • C = 2πr = πd • A = πr²

Circle Calculator

What is a Circle?

A circle is a two-dimensional shape with all points equidistant from a central point called the center. The distance from the center to any point on the circle is called the radius.

Formulas for Circles

Let r be the radius, d be the diameter, C be the circumference, and A be the area. Then:

  1. Radius: r=d2
  2. Diameter: d=2r
  3. Circumference: C=2πr
  4. Area: A=πr2

Step-by-Step Calculations

Let's calculate these properties for a circle with radius r=5 units:

  1. Radius: r=5 units
  2. Diameter: d=2×r=10 units
  3. Circumference: C=2×π×r=31.42 units
  4. Area: A=π×r2=78.54 square units

Visual Representation

Radius = 5 units Diameter = 10 units Center Calculations: 1. Radius (r) = 5 2. Diameter = 2r = 10 3. C = 2πr = 31.42 4. A = πr² = 78.54 Legend: Radius Diameter Circumference = 31.42 units Area = 78.54 sq units

This diagram illustrates the circle with the calculated dimensions and properties.