Hollow Cylinder (Tube) Volume Calculator
Find the volume of a pipe, tube or washer from its outer radius, inner radius and length — the material in the wall, not the empty bore.
How it works
Volume = π · (R² − r²) · h · Ring area = π · (R² − r²) · Wall thickness = R − r
A hollow cylinder — a pipe, tube or washer — is a full cylinder with a smaller cylinder removed from its centre. So its material volume is the outer cylinder πR²h minus the bore πr²h, which factors neatly into π(R² − r²)h. The ring you see end-on is called an annulus, and its area π(R² − r²) times the length gives the same volume. Only the wall is counted; the empty bore holds none of the material.
Worked example
For an outer radius of 5, inner radius of 3 and length 10: the ring area is π(5² − 3²) = π(25 − 9) = 16π ≈ 50.2655, and the wall volume is 16π × 10 = 160π ≈ 502.6548 cubic units. The solid cylinder would be π × 25 × 10 = 250π ≈ 785.3982, so the hollow core removes 90π ≈ 282.7433.
Sources: Cylinder — Wikipedia
Frequently asked questions
How do I get the weight of a pipe from this?
Multiply the wall volume by the material density in consistent units. If the volume is in cm³ and you use density in g/cm³ (e.g. steel ≈ 7.85), the product is the mass in grams. Convert to kilograms by dividing by 1000.
What if I only know the wall thickness, not the inner radius?
Subtract the thickness from the outer radius: inner radius = outer radius − wall thickness. A 5 cm outer radius with a 2 cm wall has a 3 cm inner radius, which is exactly the example above.
What is the volume the pipe can carry?
That is the bore, not the wall — it equals πr²h using the inner radius. This calculator reports the material volume; subtract the wall volume from the solid cylinder volume shown to recover the carrying capacity.
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This calculator is for educational purposes. Double-check important results before acting on them.