HP to GPM Calculator: Convert Horsepower to Flow Rate
Calculate the flow rate in gallons per minute (GPM) for a pump based on the horsepower (HP) and pressure in feet of head. This calculator helps you determine the flow rate achievable with a given pump power.
Understanding HP to GPM Conversion
Converting horsepower (HP) to gallons per minute (GPM) is essential for determining the flow rate achievable with a given pump power. This calculation helps in selecting the right pump for your application and ensuring efficient operation.
Key Factors in HP to GPM Calculation
Several factors influence the flow rate achievable with a pump:
| Factor | Description | Impact on GPM |
|---|---|---|
| Horsepower (HP) | Power available to the pump | Higher HP allows for higher GPM |
| Pressure (ft of head) | Total dynamic head the pump must overcome | Higher pressure reduces achievable GPM |
| Pump Efficiency | Percentage of input power converted to useful work | Higher efficiency increases achievable GPM |
Formula for HP to GPM Conversion
The formula to calculate flow rate (GPM) from horsepower (HP) is:
GPM = (HP × 3960 × Efficiency) / Pressure
Where:
- HP: Pump power in horsepower
- Pressure: Total dynamic head in feet
- Efficiency: Pump efficiency as a percentage (e.g., 75% = 0.75)
Common Applications
| Application | Typical HP Range | Typical GPM Range |
|---|---|---|
| Residential Water Supply | 0.5-2 HP | 5-20 GPM |
| Irrigation Systems | 1-5 HP | 10-50 GPM |
| Industrial Processes | 5-50 HP | 50-500 GPM |
| Fire Protection | 10-100 HP | 100-1000 GPM |
Frequently Asked Questions
What is the relationship between HP and GPM?
HP (horsepower) measures pump power, while GPM (gallons per minute) measures flow rate. The relationship depends on pressure and pump efficiency.
How does pump efficiency affect GPM?
Higher efficiency pumps can achieve higher flow rates (GPM) with the same horsepower compared to lower efficiency pumps.
What is total dynamic head (TDH)?
TDH is the total pressure a pump must overcome, including static lift, friction loss, and pressure requirements.
Can I use this calculator for any liquid?
This calculator assumes water as the pumped liquid. For other liquids, adjust for specific gravity and viscosity.
What is the 3960 constant in the formula?
The constant 3960 is derived from the conversion factors for GPM, feet of head, and horsepower.