Friction Loss Calculator
Calculate the pressure loss due to friction in a pipe using the Darcy-Weisbach equation. Enter pipe diameter, length, flow rate, and fluid properties.
Published by:
isCalculator Editorial Team
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How to Use the Friction Loss Calculator
This calculator estimates the pressure loss (in psi) due to friction in a pipe carrying water or other fluids. All inputs must be in Imperial units (inches, feet, gallons per minute).
- Enter Pipe Diameter (inches) – e.g., 2 for a 2-inch pipe.
- Enter Pipe Length (feet) – e.g., 100.
- Enter Flow Rate (GPM) – e.g., 50.
- Adjust defaults (optional): Pipe Roughness (ft, default 0.0005 for steel), Kinematic Viscosity (ft²/s, default 1.21e-5 for water), Fluid Density (lb/ft³, default 62.4 for water).
- Click "Calculate Friction Loss".
Result: The pressure loss in psi appears, along with step-by-step calculations (velocity, Reynolds number, friction factor, head loss).
Tip: Ensure all values are positive. The calculator uses the Colebrook equation for turbulent flow and the Hagen-Poiseuille equation for laminar flow (Re < 2000).
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Frequently Asked Questions
Friction loss is the pressure drop that occurs when a fluid flows through a pipe due to viscous shear stresses and turbulence. It is calculated using the Darcy-Weisbach equation.
Inputs: diameter in inches, length in feet, flow rate in GPM, roughness in feet, viscosity in ft²/s, density in lb/ft³. Output: pressure loss in psi.
For laminar flow (Re < 2000), f = 64/Re. For turbulent flow, the Colebrook equation is solved iteratively.