Pipe Flow Calculator

Calculate flow rate, velocity & Reynolds number | 🌊 For fluid mechanics & piping design

Quick presets:
Flow Rate (Q)
0.00 m³/s
Volumetric flow rate through pipe
Fluid Velocity (v)
0.00 m/s
Reynolds Number (Re)
0.00
Flow Regime
-
📐 Q = (π × ΔP × D⁴) / (128 × μ × L) | v = Q / A | Re = ρ × v × D / μ

📖 How to Use This Pipe Flow Calculator

1
Enter pipe diameter (D) – The internal diameter of the pipe in millimeters.
2
Enter pressure drop (ΔP) – The pressure difference between pipe ends in kPa.
3
Enter pipe length (L) – The total length of the pipe in meters.
4
Select fluid type – Choose from common fluids or enter custom properties.
5
Click "Calculate Flow" – Get flow rate, velocity, and Reynolds number instantly.

🌊 Understanding Pipe Flow

Pipe flow analysis is essential for designing piping systems, pumps, and fluid transport systems. The flow rate, velocity, and Reynolds number help determine the flow regime and pressure losses.

Q = (π × ΔP × D⁴) / (128 × μ × L)
v = Q / A (where A = πD²/4)
Re = ρ × v × D / μ

💡 Practical Applications

❓ Frequently Asked Questions

What is the Reynolds number and why is it important?
The Reynolds number (Re) determines the flow regime: Re < 2300 is laminar, Re > 4000 is turbulent, and between 2300-4000 is transitional. It's critical for calculating friction factors and pressure losses.
What is the difference between laminar and turbulent flow?
Laminar flow is smooth and orderly, with layers of fluid sliding past each other. Turbulent flow is chaotic and mixed, with eddies and vortices. Turbulent flow has higher pressure losses.
What fluids can I use with this calculator?
You can use water, air, oil, glycerin, or any custom fluid by entering its density and viscosity. The calculator assumes Newtonian fluids.