Pump Horsepower Calculator
Calculate pump shaft power, hydraulic power, and specific speed for fluid pumping systems
Calculate Pump Power Requirements
Volumetric flow rate of fluid through the pump
Total head the pump must overcome
Density of the fluid being pumped (water: 1000 kg/m³)
Overall pump efficiency (0.7-0.85 typical range)
Rotational speed of pump impeller
Pump Power Results
Hydraulic Power Formula: Ph = Q × H × ρ × g
Shaft Power Formula: Ps = Ph / η
Efficiency: η = Ph / Ps = 80.0%
Power Analysis
Example Calculation
Water Pumping System
Discharge (Q): 10 m³/h = 0.00278 m³/s
Differential Head (H): 3 m
Fluid Density (ρ): 1000 kg/m³ (water)
Pump Efficiency (η): 0.79 (79%)
Gravity (g): 9.81 m/s²
Step-by-Step Calculation
1. Hydraulic Power: Ph = Q × H × ρ × g
Ph = 0.00278 × 3 × 1000 × 9.81 = 81.75 W
2. Shaft Power: Ps = Ph / η
Ps = 81.75 / 0.79 = 103.48 W
Result: 0.103 kW shaft power required
Pump Types by Specific Speed
Centrifugal Pumps
Ns = 0.1 - 1.0
High head, low flow
Mixed Flow Pumps
Ns = 1.0 - 3.0
Medium head, medium flow
Axial Flow Pumps
Ns = 3.0 - 10.0
Low head, high flow
Common Fluid Densities
Pump Design Tips
Higher efficiency reduces operating costs
Pump should operate near best efficiency point
Consider NPSH requirements to avoid cavitation
Variable frequency drives can improve efficiency
Regular maintenance maintains performance
Understanding Pump Horsepower and Power Calculations
What is Pump Power?
Pump power refers to the energy required to move fluid through a pumping system. There are two main types: hydraulic power (useful power delivered to the fluid) and shaft power (total mechanical power input to the pump).
Key Components
- •Discharge (Q): Volume flow rate of fluid
- •Head (H): Total energy per unit weight of fluid
- •Density (ρ): Mass per unit volume of fluid
- •Efficiency (η): Ratio of useful power to input power
Power Formulas
Hydraulic Power
Ph = Q × H × ρ × g
The useful power transmitted to the fluid
Shaft Power
Ps = Ph / η
The mechanical power input to the pump shaft
Specific Speed
Ns = N × Q^0.5 / (g × H)^0.75
Dimensionless parameter for pump selection
Pump Efficiency
Typical pump efficiencies range from 70-85%. Higher efficiency pumps reduce energy costs but may have higher initial costs. The efficiency depends on pump design, operating conditions, and maintenance.
Operating Point
Pumps should operate near their best efficiency point (BEP) for optimal performance. Operating far from BEP can lead to increased wear, vibration, and energy consumption.
Power Units
Power can be expressed in watts (W), kilowatts (kW), or horsepower (HP). 1 HP = 745.7 W. Shaft power is always greater than hydraulic power due to losses.