Circle Radius = 4
William Howard
Published Jan 20, 2026
A circle has Radius = 4
Calculate Area, Circumference, Diameter
Calculate circumference (C):
C = 2πr
C = 2π * 4
C = 8π or 25.1327
Calculate diameter (d):
d = 2r
d = 2 * 4
d = 8
Calculate Area (A):
A = πr2
A = π * 42
A = 16π or 50.2655
Final Answers
C = 8π or 25.1327
d = 8
A = 16π or 50.2655
You have 1 free calculations remaining
What is the Answer?
C = 8π or 25.1327
d = 8
A = 16π or 50.2655
How does the Circles Calculator work?
Free Circles Calculator - Calculates and solves for Radius, Diameter, Circumference, and Area of a Circle.
This calculator has 1 input.
What 3 formulas are used for the Circles Calculator?
What 7 concepts are covered in the Circles Calculator?
- area
- Number of square units covering the shape
- circle
- the set of all points in the plane that are a fixed distance from a fixed point
- circles
- circumference
- the perimeter of a circle or ellips
- diameter
- distance from two endpoints of a circle through the center
d = 2r - origin
- On a two digit coordinate plane, the point (0, 0), where the x-axis and y-axis cross.
- radius
- Distance from the center of a circle to the edge
C/2π
