Pipe & Fitting Pressure Loss Calculator

Planning estimator for irrigation systems using rigid PVC or flexible tubing. Uses the Hazen–Williams equation with conservative assumptions.

Pressure loss depends far more on flow rate than pipe length. Doubling flow increases friction dramatically.

Pipe Material
Rigid PVC Flexible PVC / Poly Pipe Inside Diameter (inches)
½" ¾" 1" 1¼" 1½" 2" 3" 4" 6" Straight Pipe Length (feet)
Flow Rate (GPM)

Fittings

45° Elbows
90° Long-Radius Elbows
90° Standard Elbows
Tees (Straight Through)
Tees (Branch Flow)
Valves (Fully Open)
Calculate Pressure Loss

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Friction Formula Used

h_f = 4.52 × (Q^1.85 × L) / (C^1.85 × D^4.87)

Where Q = flow (GPM), L = total equivalent length (ft), D = pipe diameter (in), C = roughness coefficient.