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Hollow tube & pipe calculator

Outer wall minus the bore: get the material volume of a pipe or the liquid it can hold, from outer and inner diameters.

A pipe or tube is a cylinder with a hole down the middle, so its volume is the outer cylinder minus the inner one. This hollow tube & pipe calculator asks for the outer and inner diameters and returns the wall (material) volume, the bore capacity, or both.

How to work it out

  1. Measure the outer diameter and the inner (bore) diameter.
  2. Halve each to get the outer radius R and inner radius r.
  3. Find the ring area: π (R² − r²).
  4. Multiply by the length to get the wall (material) volume.
  5. Read the bore capacity and material volume separately.

Worked example. Take a cylinder with a diameter of 10 cm (so a radius of 5 cm) and a height of 25 cm. The base area is π × 5² = 78.54 cm², and multiplying by the height gives a volume of about 1.96 litres (1,963 cm³ · 0.52 US gallons).

Keep the two results apart: the wall (material) volume is the metal or plastic itself, while the bore capacity is what the pipe can carry. They are not interchangeable.

Every hollow tube & pipe page

Each page below targets a specific question and opens with the calculator ready to go:

Good to know

How do I find the volume of a hollow cylinder?
Subtract the inner cylinder from the outer one: V = π h (R² − r²), where R is the outer radius and r is the inner radius. The tool asks for diameters and does the halving for you.
What is the difference between material volume and capacity?
Material volume is the solid in the wall; capacity is the empty space in the bore. A pipe's coating budget uses material volume; what it carries uses the bore capacity.
Must the inner diameter be smaller than the outer?
Yes — the bore has to fit inside the wall. The calculator will flag it if the inner value is not smaller.

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