Pipe Flow Rate Calculator
Calculate flow rate, velocity, Reynolds number, and pressure drop in pipes using Darcy-Weisbach and Hazen-Williams equations. Engineering calculator for plumbing, hydraulics, water supply systems, and civil engineering fluid mechanics applications.
Bernoulli & Hagen-Poiseuille Equation
Q = (π × ΔP × d⁴) / (128 × μ × L)Variables:
- QFlow rate (m³/s)Flow rate (m³/s)
- ΔPPressure difference (Pa)Pressure difference (Pa)
- dPipe diameter (m)Pipe diameter (m)
- μDynamic viscosity (Pa·s)Dynamic viscosity (Pa·s)
- LPipe length (m)Pipe length (m)
How to Use the KalkuLab Pipe Flow Calculator
- 1
Enter Pipe Parameters
Enter diameter (d), pressure difference (ΔP), pipe length (L), and dynamic viscosity (μ).
- 2
Calculate
Press Calculate to apply the Hagen-Poiseuille equation.
- 3
View Flow Rate
Get the volumetric flow rate (Q) in m³/s or L/s.
Examples
Water Pipe
Problem:
d=0.1m, ΔP=10000Pa, L=10m, μ=0.001Pa·s. Find Q.
Solution:
- 1.Q = (π × 10000 × 0.1⁴) / (128 × 0.001 × 10)
- 2.Q ≈ 0.00245 m³/s
Result:Q ≈ 2.45 L/s
The pipe flow rate is approximately 2.45 L/s.
Frequently Asked Questions
Which fluids does this apply to?
Newtonian fluids (water, oil) with laminar flow (Re < 2000).
What is the Reynolds number (Re)?
Re = ρvd/μ. If Re > 4000, the flow is turbulent and this formula no longer applies.