Darcy–Weisbach ΔP Calculator

Frictional pressure drop in a pipe

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Darcy–Weisbach ΔP

Frictional pressure drop in a pipe

$$\Delta P = f_D \dfrac{L}{D} \dfrac{\rho v^2}{2}$$

Laminar: $f_D=64/Re$. Turbulent: use Swamee-Jain below. Fanning $f=f_D/4$.

f_D

L (m)

D (m)

ρ (kg/m³)

v (m/s)

All fields required; D nonzero.

Pressure Drop ΔP

—Pa

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