Input Parameters
About This Calculator
- Based on the continuity equation: Q = v × A
- Recommended velocity: Water pipes 0.5–3.0 m/s, Air ducts 3–15 m/s
- Low velocity: oversized pipe, not economical
- High velocity: increased friction losses, potential noise
How this pipe flow calculator works
This tool is based on the continuity equation Q = v x A. Provide any two of flow rate, internal diameter, and velocity to solve the third value.
Inputs explained
- Flow rate is entered in m³/h and converted to m³/s for calculation.
- Pipe diameter is the internal diameter, not nominal pipe size.
- Velocity is the average flow velocity in the pipe cross-section.
- Fluid type selects the recommended velocity range used for the result comment.
FAQ
Why is internal diameter important?
Flow area depends on internal diameter. Nominal pipe size can differ from actual internal diameter by material and schedule.
What happens if velocity is too high?
High velocity may increase pressure drop, noise, erosion risk, and pump energy use.
What happens if velocity is too low?
Low velocity may indicate oversized pipe and uneconomical material cost.