To calculate the surface area of a circle, simply enter the radius into the textbox below. Once entered click on the Calculate button, and the result will be displayed below the form. In case it’s been a while since your last geometry lesson, the radius is half the length of the diameter;-)!

Enter Radius:

Other tools that you may be interested in:
Circle Circumference Calculation Tool
Circle Diameter and Radius from Surface Area Calculation Tool
Circle Surface, Radius and Diameter from Circumference Calculation Tool
Sphere Volume (V) and Surface (S) Calculation Tool
Sphere Circumference (c) Calculation Tool
Sphere Diameter (d) and Radius (r) from Volume (V) Calculator
Sphere Diameter (d) and Radius (r) from Surface (S) Calculator
Sphere Volume (V) from Surface (S) Calculator
Sphere Surface (S) from Volume (V) Calculator

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