Hollow tube & pipe
Volume Tube 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 volume tube calculator asks for the outer and inner diameters and returns the wall (material) volume, the bore capacity, or both.
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.
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.
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.
What people work out next
Most jobs need one or two more things once the volume lands. The common follow-ups, with the numbers you need, are below:
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.
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.
Where people go wrong
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.
One result, every unit
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.
What to work out next
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:
When this comes in handy
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
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.
Frequently asked questions
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.What is the difference between material volume and capacity?
Must the inner diameter be smaller than the outer?
What is the formula for the volume of a cylinder?
V = π r² h — the area of the circular base (π r²) multiplied by the height (h). If you have the diameter instead of the radius, halve it first: r = d ÷ 2.