Physics

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Pipe Flow Calculator.

Calculate laminar volumetric flow through a round pipe.

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01

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Results update as you type.

Flow rate: 0.003927 m³/s

Flow rate

0.000000m³/s

Results update automatically as you type.

Use Cases

Engineering Design of Fluid Systems

Engineers can use this calculator to estimate the flow rate through small-diameter pipes in laminar flow conditions, such as in microfluidics or hydraulic systems, to ensure proper system design.

Example: Designing a capillary tube for a lab-on-a-chip device with a given pressure drop and dimensions.

Frequently Asked Questions

What is the Pipe Flow Calculator used for?
This calculator determines the volumetric flow rate of a fluid in laminar flow through a round pipe. It uses the Hagen-Poiseuille equation, which requires the pressure drop across the pipe, the pipe radius, the pipe length, and the dynamic viscosity of the fluid.
What units are used in the Pipe Flow Calculator?
The calculator uses SI units: pressure drop in Pascals (Pa), pipe radius in meters (m), pipe length in meters (m), and dynamic viscosity in Pascal-seconds (Pa·s). The result is the volumetric flow rate in cubic meters per second (m³/s).
Does the Pipe Flow Calculator work for turbulent flow?
No, this calculator is specifically for laminar flow, where the Reynolds number is typically below 2300. For turbulent flow, different equations are needed. The calculator assumes laminar conditions based on the inputs provided.

Tips & Common Mistakes

Tips

  • Ensure all inputs are in the correct SI units: Pa for pressure drop, m for radius and length, and Pa·s for viscosity.
  • For accurate results, verify that the flow is laminar by estimating the Reynolds number (typically < 2300) based on your fluid and pipe dimensions.
  • If the pipe is not circular, this calculator is not applicable; it is specifically for round pipes.
  • Double-check your pressure drop value: it should be the difference in pressure between the inlet and outlet of the pipe.

Common Mistakes to Avoid

  • Using diameter instead of radius: the calculator requires the pipe radius, not the diameter. Remember to divide the diameter by 2.
  • Mixing units: for example, entering pressure drop in bar instead of Pa, or viscosity in cP instead of Pa·s, will lead to incorrect results.
  • Assuming the calculator works for turbulent flow: this calculator is only valid for laminar flow conditions.

Last updated: August 13, 2026