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Hollow Cylinder Volume Calculator

Calculate the volume, wall thickness, inner/outer radius and diameter, surface area, and mass of a hollow cylinder or cylindrical pipe with step-by-step math.

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What Is a Hollow Cylinder?

A hollow cylinder (also known as a cylindrical shell, circular tube, or pipe) is a three-dimensional geometric solid bounded by two concentric cylindrical surfaces sharing the same rotational axis and height. It consists of an outer cylinder of radius $R$ (or outer diameter $D$) from which a coaxial inner cylindrical core of radius $r$ (or inner diameter $d$) has been removed.

Hollow Cylinder Formulas

The geometry of a cylindrical shell involves several key formulas derived from basic cylinder dimensions:

1. Wall Thickness ($t$)

The wall thickness is the radial difference between the outer and inner radius:

$$t = R - r = \frac{D - d}{2}$$

2. Annular Cross-Sectional Area ($A_{cs}$)

The cross-sectional area perpendicular to the length of the cylinder is an annulus (a ring):

$$A_{cs} = \pi (R^2 - r^2) = \pi (R - r)(R + r) = \pi t (2r + t)$$

3. Hollow Cylinder (Shell) Volume ($V_H$)

The material volume of the solid shell is the cross-sectional area multiplied by the cylinder length or height $h$:

$$V_H = \pi (R^2 - r^2) h = \pi (t^2 + 2tr) h$$

Alternatively, this equals the difference between the total outer cylinder volume and the inner void volume:

$$V_H = V_{outer} - V_{inner} = \pi R^2 h - \pi r^2 h$$

4. Surface Area Formulas

  • Outer Lateral Area: $A_{lat,out} = 2\pi R h$
  • Inner Lateral Area: $A_{lat,in} = 2\pi r h$
  • Total Lateral Area: $A_{lat} = 2\pi (R + r) h$
  • Two End Rings (Caps): $A_{caps} = 2\pi (R^2 - r^2)$
  • Total Surface Area: $A_{tot} = 2\pi (R + r) h + 2\pi (R^2 - r^2)$

5. Mass and Weight Calculation

The mass $m$ of the hollow cylinder depends on the material density $\rho$ and the solid shell volume $V_H$:

$$m = \rho \times V_H$$

Common Material Densities

Material Density (g/cm³) Density (kg/m³)
Structural Steel 7.85 7,850
Aluminum 2.70 2,700
Copper 8.96 8,960
Brass 8.50 8,500
PVC Plastic 1.38 1,380
Concrete 2.40 2,400

For other 3D geometry calculations, check out our Cylinder Calculator, Pipe Volume Calculator, and Cross-Sectional Area Calculator.

Frequently Asked Questions

How do you calculate the volume of a hollow cylinder?

To find the material volume of a hollow cylinder, subtract the inner cavity cylinder volume from the outer cylinder volume: $V_H = \pi(R^2 - r^2)h$, where $R$ is the outer radius, $r$ is the inner radius, and $h$ is the height or length.

What is the difference between inner volume and hollow cylinder volume?

The inner volume $V_{in} = \pi r^2 h$ measures the internal fluid capacity or empty cavity inside the tube. The hollow cylinder volume $V_H = \pi(R^2 - r^2)h$ measures the solid material making up the pipe walls.

What is the volume of a hollow cylinder with D = 10 cm, d = 6 cm, and height = 20 cm?

First find radii: $R = 5\text{ cm}$ and $r = 3\text{ cm}$. Calculate the cross-sectional ring area: $A_{cs} = \pi(5^2 - 3^2) = \pi(25 - 9) = 16\pi \approx 50.265\text{ cm}^2$. Multiply by height $h = 20\text{ cm}$: $V_H = 50.265 \times 20 \approx 1,005.31\text{ cm}^3$.

Does the formula change if the inner cylinder is off-center (eccentric)?

No. As long as the inner hole is parallel to the outer cylinder throughout the entire height $h$, Cavalieri's principle guarantees that the solid material volume remains exactly $V_H = \pi(R^2 - r^2)h$.

How do I find wall thickness from outer diameter and inner diameter?

Subtract inner diameter $d$ from outer diameter $D$ and divide by 2: $t = (D - d)/2$.