A tube is a hollow cylinder — a pipe, straw, or ring extrusion.
About this calculator
A tube is a hollow cylinder — a pipe, straw, or ring extrusion. Wall volume equals the outer solid minus the inner bore: π(R² − r²)h. When inner radius is 0 you recover a solid cylinder.
Wall thickness R − r drives material cost for PVC pipe, metal tubing, and concrete rings. The calculator also reports outer volume, core volume, and thickness so you can cross-check against a solid [[cylinder]] of radius R.
Inner radius must stay smaller than outer radius. For square hollow sections use rectangular prism math instead. Pair with [[volume]] for mixed tanks, [[surface-area]] for outer wrap area, and [[density]] when converting wall volume to mass.
Common uses
- PVC or metal pipe material volume for weight estimates
- Concrete ring or culvert wall volume
- 3D print filament for hollow cylindrical parts
- Compare wall volume at different bore sizes
- Lab glass tubing capacity vs wall material
Frequently asked questions
What is the wall volume when R = 5, r = 3, h = 10?
V = π(25 − 9) × 10 = 160π ≈ 502.65 cubic units. Wall thickness = 2 units.
What if inner radius is zero?
The tube becomes a solid cylinder. Wall volume equals πR²h, the full outer volume.
Can inner radius equal outer radius?
No — that would leave no wall material. Inner radius must stay strictly less than outer radius.
Does this give fluid capacity inside the pipe?
The hollow core volume πr²h is the fluid capacity. Wall volume is only the material between r and R.