Pipe Volume Calculator
Calculate pipe volume and water capacity from diameter and length in litres or gallons for plumbing and irrigation jobs, free in your browser.
Enter Values
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the inside diameter (mm) and length (m).
- Read the volume in litres and cubic metres.
How it works
Volume = π × radius² × length, using the inside radius (half the inside diameter).
Worked example
50 mm bore, 10 m. ≈ 19.63 litres.
Common mistakes
- Using the outside diameter — capacity depends on the inside bore.
- Mixing units — diameter in mm, length in m (the tool handles the conversion).
Frequently asked questions
How do I calculate pipe volume?
Volume = π × radius² × length. Use the internal diameter, since wall thickness reduces the bore that actually holds fluid.
Why use internal diameter, not outer?
Capacity depends on the bore the fluid flows through; the outside diameter overstates volume, especially on thick-walled pipe.
Inside or outside diameter?
Inside — the bore is what holds water. Pipe specs often quote outside diameter, so check.
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Cite this tool
Zerdly. (2026). Pipe Volume Calculator. Retrieved from https://www.zerdly.com/tools/pipe-volume-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.