Pump Head

Water pump sizing with Darcy–Weisbach friction, equivalent-length fittings, NPSHa, and motor estimate.

Duty point —
Design TDH
—ft
Rounded up for selection
Flow
—GPM
Required capacity
Brake HP
—BHP
At assumed pump η
Motor size
—HP
~1.15 service factor

System schematic

ELEVATIONS · FLOW
Suction 0 ft Discharge 40 ft PUMP 5 ft Δz — — GPM —

System curve

H vs Q

TDH breakdown

ft
Static head
—
Pressure Δ
—
Friction + margin
—
Exit velocity
—
TDH
—

Pipe velocity

ft/s
—
Suction
—
—
Discharge
—

NPSH available vs required

MARGIN
NPSHa—
NPSHr—
Margin—
—
—

Hydraulic details

CALC
Specific gravity
—
Kinematic ν (ft²/s)
—
Vapor head (ft)
—
Re suction
—
Re discharge
—
Regime (disch.)
—
f suction
—
f discharge
—
hf suction (ft)
—
hf discharge (ft)
—
Water HP
—
Input kW
—

Pipe runs

Run ID L Leq V hf Note

PHP engine: calc.php · Live UI: assets/calc.js · Same equations as the spreadsheet. Run with php -S localhost:8765 -t app from the project folder.