Pump Head Calculator Formula

Understand the math behind the pump head calculator. Each variable explained with a worked example.

Formulas Used

Total Dynamic Head

total_head = static_head + friction_loss + pressure_head

Equivalent Pressure

total_head_psi = (static_head + friction_loss + pressure_head) * 0.4333

Variables

VariableDescriptionDefault
static_headStatic Head (elevation)(ft)30
friction_lossFriction Head Loss(ft)10
pressure_headRequired Pressure Head(ft)46

How It Works

Total Dynamic Head (TDH)

TDH = Static Head + Friction Loss + Pressure Head

Static head is the vertical distance the pump must lift water. Friction loss accounts for resistance in the piping. Pressure head is any residual pressure needed at the delivery point (20 psi = 46 ft). Select a pump whose curve exceeds TDH at your design flow rate.

Worked Example

Pump lifts water 30 ft, 10 ft friction loss, need 20 psi (46 ft) at outlet.

static_head = 30friction_loss = 10pressure_head = 46
  1. 01TDH = 30 + 10 + 46 = 86 ft
  2. 02In psi = 86 x 0.4333 = 37.3 psi
  3. 03Select a pump rated above 86 ft TDH at the required GPM.

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