How do I calculate pump power?

Hydraulic power P = ρ × g × Q × H, where ρ is density, g is gravity, Q is flow, and H is total head. Divide by pump efficiency for motor power.

Total head is the sum of static head (elevation difference), pressure head, and friction head loss. It's the total energy the pump must add.

How does efficiency affect power?

Motor power = hydraulic power ÷ efficiency. A 60% efficient pump needs 67% more input power than a 100% efficient one for the same output.

Pump Power Calculator — Hydraulic Power from Flow & Head

Calculate hydraulic pump power from flow rate, head, and fluid density. Estimate the motor power required including pump efficiency.

Fluid Velocity (m/s)

Pipe Diameter (m)

Kinematic Viscosity ν (m²/s)

Common ν: Water 20°C = 1.004×10⁻⁶ · Air 20°C = 1.516×10⁻⁵ m²/s

⟨∿⟩ Fluids Reference: All calculations use SI units (Pa, m³/s, W, K). Moody friction factor uses Blasius smooth-pipe approximation. Bernoulli assumes ideal, incompressible, steady flow along a streamline.

How It Works

Calculate hydraulic pump power from flow rate, head, and fluid density. Estimate the motor power required including pump efficiency

Each component has a specific meaning:

Flow rate — The flow rate recorded for the patient or scenario being assessed.
Head — The head recorded for the patient or scenario being assessed.
Fluid density — The fluid density recorded for the patient or scenario being assessed.

Note: Interpret the pump power result against the clinical thresholds and context described above.

How to Use

Enter the flow rate, head, fluid density for the patient or scenario you are assessing. Calculate hydraulic pump power from flow rate, head, and fluid density. Estimate the motor power required including pump efficiency. Use the pump power result to inform your clinical assessment.

Related Calculators

Pump NPSH

Engineering

Pump Specific Speed

Engineering

Pipe Flow Rate

Fluids

Head Loss (Darcy-Weisbach)