○ • Reviewed 2026-11-05

Sphere and Enclosing Cylinder Comparison

Compare a sphere with its snug enclosing cylinder, whose radius is r and height is 2r.

Quick answer

The short version

The cylinder volume is 2πr³ and the sphere volume is 4πr³/3, so the sphere occupies exactly two thirds of the cylinder.

Vcylinder = 2πr³; Vsphere = 4πr³/3

Interactive tool

Calculate cylinder vs sphere

Values convert through SI units; displayed digits are rounded only at the end.

Vcyl = 2πr³; Vsphere = 4πr³/3

r h
Result
—cm³

Complete the fields to calculate.

How the result changes

Calculated from the current dimensions
How the result changesComplete the calculator to display a graph.
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Worked calculation

Result: At r = 5, the cylinder volume is 785.398163 and the sphere volume is 523.598776 cubic units.

01 • Guide

The enclosing dimensions

A snug cylinder around a sphere has the same radius and a height equal to the sphere’s diameter, 2r. Forgetting that height causes the comparison to be inconsistent.

Keep the full precision of intermediate values and round only the final display. This avoids compounding error when a derived radius or converted unit is used in another step.

02 • Guide

Archimedes’ ratio

Dividing sphere volume by enclosing-cylinder volume gives (4/3)/(2) = 2/3. The remaining one third belongs to the regions inside the cylinder but outside the sphere.

The calculator validates physical limits before displaying a result. Blank or impossible inputs never produce a stale value, NaN or Infinity.

03 • Guide

How scaling behaves

Both volumes scale with r³. Doubling radius multiplies each volume by eight but never changes the two-thirds ratio, as the live comparison graph demonstrates.

Interpretation

How to use the result responsibly

The answer models an ideal geometric cylinder. Manufacturing tolerances, wall thickness, rounded ends, deformation, tank tilt and measurement uncertainty can all shift a real value. Use inside dimensions for capacity and outside dimensions for occupied space. For safety, compliance, dosing, structural or purchasing decisions, compare the estimate with drawings, calibration data or a qualified professional.

Dimensional checks help catch mistakes: a volume result must carry cubic units, an area result square units and a derived radius or height linear units. If changing one unit alters the represented physical size, a conversion step was missed.

Clear answers

Cylinder vs sphere: common questions

Why is cylinder height 2r?

Because it must span the sphere’s full diameter.

What is the empty fraction around the sphere?

One third of the enclosing cylinder’s volume.

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