DIY & materials
Pipe volume and flow Calculator
Convert internal pipe diameter and velocity to volume and flow. This free pipe volume and flow calculator shows the calculation and its assumptions so you can compare your own figures.
Your results
Convert internal pipe diameter and velocity to volume and flow.
Calculated outcomes
- Cross Section M2
- 0.0005 m²
- Flow Litres Second
- 0.491 L/s
- Fill Seconds
- 30 s
Assumptions and estimates
- Method: Cross-section = π × diameter² ÷ 4. Volume = area × length; flow = area × velocity.
- Uses the internal diameter. Does not calculate pressure drop, pump selection, pipe roughness, fittings or allowable velocities.
Useful next steps
- Use Compare options to test an alternative side by side.
- Copy, print or download a record of this calculation when you need one.
Reports open your email app addressed to s@s1.ie with the public page address only. Your inputs are never added.
How the pipe volume and flow calculation works
Cross-section = π × diameter² ÷ 4. Volume = area × length; flow = area × velocity.
Uses the internal diameter. Does not calculate pressure drop, pump selection, pipe roughness, fittings or allowable velocities.
Using this calculator
- Enter your own figures in the labelled inputs. Keep the currencies, units and time periods consistent.
- Choose any applicable rate profile, pattern or assumption shown for this tool. Open additional inputs when relevant.
- Review volume litres and flow litres minute, then read the stated assumptions and eligibility conditions before using the result.
Worked example
This is a static example using illustrative inputs, not facts about you or today’s date. The displayed eligibility selections and assumptions apply only to this example.
See example inputs
- Internal diameter (mm)
- 25
- Pipe length (m)
- 30
- Mean water velocity (m/s)
- 1
- Volume Litres
- 14.726 L
- Flow Litres Minute
- 29.45 L/min