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Circle & Sphere Calculator

Calculate area, circumference, volume, and surface area for circles and spheres. Compute from either radius or diameter.

Input value

Formulas

Area = ฯ€rยฒ

Circumference = 2ฯ€r

Diameter = 2r

rArea = ฯ€rยฒCircumference = 2ฯ€r
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How to Use

Step 1

Enter Radius

Enter Radius

Enter radius or diameter

Step 2

Calculate

Calculate

Area, circumference, volume calculated automatically

Step 3

View Result

View Result

Check all calculation results

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Features

Circle & Sphere

Show both 2D (circle) and 3D (sphere) calculations

Reverse Calculation

Reverse-calculate radius from area or circumference

Sector Support

Also calculate sector area and arc length

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FAQ

ฯ€rยฒ (pi ร— radius squared).