# Free Online Darcy-Weisbach Pipe Head Loss Calculator

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## Darcy-Weisbach Pipe Head Loss at Given Diameter, Roughness, and Flow

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Inputs
 Flow, Q m^3/s l/s Ml/d cfs gpm MGD X Pipe diameter, d0 m mm ft in X Pipe length, L m mm ft in X Darcy-Weisbach absolute roughness, e m mm ft in X Kinematic viscosity, v, in m2/sec (1E-6 for clean water at room temperature) X Total combined junction loss coefficient, k X Downstream EGL m H2O mm H2O kPa ft H2O in H2O psi X
Results
 Flow area, a Flow area, a m^2 mm^2 ft^2 sq. in. X Wetted perimeter, Pw Wetted perimeter, Pw m mm ft in X Hydraulic radius, Rh Hydraulic radius, Rh m mm ft in X Velocity, v Velocity, v m/s ft/sec X Velocity head, hv Velocity head, hv m H2O mm H2O kPa ft H2O in H2O psi X Reynolds number, Re Reynolds number, Re X Flow regime Flow regime X Friction factor method Friction factor method X Friction factor, f Friction factor, f X Friction slope Friction slope rise/run % rise/run X Average shear stress (tractive force), tau Average shear stress (tractive force), tau N/m^2 psf X Friction loss, Hf Friction loss, Hf m H2O mm H2O kPa ft H2O in H2O psi X Junction loss, Hm Junction loss, Hm m H2O mm H2O kPa ft H2O in H2O psi X Total loss, Hl Total loss, Hl m H2O mm H2O kPa ft H2O in H2O psi X Downstream HGL Downstream HGL m H2O mm H2O kPa ft H2O in H2O psi X Upstream EGL Upstream EGL m H2O mm H2O kPa ft H2O in H2O psi X Upstream HGL Upstream HGL m H2O mm H2O kPa ft H2O in H2O psi X