Surface Area Calculator
Find surface area for boxes, cylinders, spheres, and cones.
Surface area
94 sq units
2(lw + lh + wh)
A sphere's neat fact
exactly 4× its shadow circle
Unfold it mentally
Surface area sums the faces: a box is three pairs of rectangles; a cylinder unrolls into a rectangle plus two circles; a cone unrolls into a circular sector plus its base. Spheres resist unrolling — Archimedes proved their 4πr² by comparison with the wrapping cylinder.
Why surface matters
Paint, wrapping, heat loss, and material costs all scale with surface, not volume. And because volume grows faster than surface as objects enlarge (the square-cube law), big things stay warm and small things dry out — biology and engineering both obey it.
Frequently asked questions
- How does the Surface Area Calculator work?
- Find surface area for boxes, cylinders, spheres, and cones.
- Is the Surface Area Calculator free to use?
- Yes. The Surface Area Calculator is completely free, runs entirely in your browser, and requires no account or sign-up. Your inputs never leave your device.
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