Hollow tube & pipe
Volume of Hollow Cylinder Calculator
Outer wall minus the bore: get the material volume of a pipe or the liquid it can hold, from outer and inner diameters.
This volume of hollow cylinder calculator keeps two very different numbers apart: the solid material in a pipe wall, and the space inside the bore. Enter outer and inner diameters plus length, and you get each one clearly labelled.
The reason a dedicated hollow-cylinder tool helps is that the two useful numbers pull in opposite directions: a thick wall means more material but less bore, a thin wall the reverse. Seeing both from one calculation stops you reaching for the wrong one.
Using the calculator
- Measure the outer diameter and the inner (bore) diameter.
- Halve each to get the outer radius R and inner radius r.
- Find the ring area: π (R² − r²).
- Multiply by the length to get the wall (material) volume.
- Read the bore capacity and material volume separately.
Getting an accurate measurement
Confirm the inner diameter is the bore, not the wall thickness. Keep every measurement in the same system, and let the tool convert between units for you.
How the volume is worked out
The volume of a hollow cylinder is:
V = π h (R² − r²)A worked example
Worked example. Take a cylinder with a diameter of 20 cm (so a radius of 10 cm) and a height of 40 cm. The base area is π × 10² = 314.16 cm², and multiplying by the height gives a volume of about 12.57 litres (12,566 cm³ · 3.32 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.
Conversions use standard factors: 1 US gallon = 231 in³, 1 Imperial gallon = 4.54609 L, 1 litre = 1000 cm³.
After you have your answer
Most jobs need one or two more things once the volume lands. The common follow-ups, with the numbers you need, are below:
What if it is a very thin tube?
The same formula applies however thin the wall — the material volume simply becomes small next to the bore, which the breakdown makes clear at a glance.
How much can the pipe carry?
The bore capacity — the space inside — is listed separately from the wall material in the result, so you can read both from a single calculation.
How do I get the weight of the pipe?
Use the wall (material) volume, not the bore, and multiply by the material density. Tick estimate weight and the tool does it once you enter a density.
What is the wall thickness from the diameters?
Wall thickness is the outer diameter minus the inner diameter, divided by two. Enter both diameters and the tool uses them to separate metal from bore automatically.
Common uses
It comes in handy across quite different tasks:
- Estimating the steel in a run of pipe
- Working out how much a tube can carry
- Costing anti-corrosion coating from surface and volume
- Comparing wall thickness options
Common mistakes to avoid
Be careful to enter the bore as a diameter, not as a thickness, and to confirm the inner value really is smaller than the outer. Then choose the right output for the job: material for weight, bore for what the pipe carries.
Getting the number in the unit you need
Showing every unit at once is about speed and safety: you see the answer in litres, gallons and cubic feet side by side, so there is no chance of applying the wrong conversion factor. Change the output unit at the top to make any of them the headline figure, switch the precision to exact if you want the value in terms of pi, and use copy-result to paste a tidy summary wherever you need it.
Keep going
Once you have your answer you may also want to work in volume formula tank capacity solid rod & bar. These related calculators pick up where this one leaves off:
The bottom line: with the radius or diameter and the height, the volume follows immediately, and the breakdown lets you hand the same number to anyone in the unit they prefer. Measure inside dimensions for anything that holds liquid, leave a little headspace at the top of a real container, and treat the geometric figure as a clean maximum rather than the final word on usable capacity.
Good to know
What units can I use?
Is the volume of a cylinder squared or cubed?
Does this work for a tank or a pipe?
How do I find the volume of a hollow cylinder?
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.