Sphere Calculator - Calculate Volume, Surface Area, Radius & Diameter
Sphere Inputs
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Enter any one value. The calculator will compute all other properties.
Calculation Results
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Understanding Spheres
What is a Sphere?
A sphere is a perfectly round 3D shape where every point on the surface is the same distance from the center. Think of balls, planets, and bubbles - they're all spheres. Unlike a circle (which is flat), a sphere occupies space and has volume.
The radius (r) is the distance from the center to any point on the surface. The diameter (d) is twice the radius and represents the distance across the sphere through its center.
Volume Formula
V = (4/3)πr³
The volume measures how much space is inside the sphere. It grows with the cube of the radius, so doubling the radius increases volume by 8 times (2³ = 8).
Surface Area Formula
A = 4πr²
The surface area measures the total area of the sphere's outer surface. It's exactly 4 times the area of a circle with the same radius.
Real-World Applications
- Engineering: Calculating tank capacities and ball bearings
- Astronomy: Estimating planet and star volumes
- Medicine: Measuring cells, tumors, and drug particles
- Sports: Designing balls for different sports (basketball, soccer, golf)
- Architecture: Dome designs and spherical structures
Quick Tips
- • A sphere has the smallest surface area for a given volume of any 3D shape
- • The volume formula has a factor of 4/3, not just π
- • Surface area is 4πr², exactly 4 times a circle's area (πr²)
- • Doubling the radius multiplies volume by 8 and surface area by 4