Pump Power Calculator

Formula

P = (ρ·g·Q·H) / (1000·η) where ρ = 1000 kg/m³, g = 9.81 m/s², Q = flow (m³/s), H = head (m), η = efficiency.

Variables

• Q — flow rate (m³/h)
• H — total dynamic head (m)
• η — pump efficiency (fraction)

Example

85 m³/h at 18 m head, 70% efficiency: P = (1000·9.81·0.0236·18)/(1000·0.7) ≈ 5.95 kW.

Application

Useful for preliminary pump motor sizing.

Limitations

This is hydraulic power only. Motor power, drive losses, NPSH and system design must be considered. Full design requires a qualified engineer.