HP to CFS Calculator
How to Convert HP to CFS
The HP to CFS Converter calculates the flow rate in cubic feet per second (CFS) from horsepower (HP), efficiency, and head using the following steps:
Step 1: Convert Head to Feet (if needed):
\( \text{Head (ft)} = \text{Head (cm)} \times 0.0328084 \)
\( \text{Head (ft)} = \text{Head (m)} \times 3.28084 \)
\( \text{Head (ft)} = \text{Head (in)} \times 0.0833333 \)
\( \text{Head (ft)} = \text{Head (ft)} \times 1 \)
Step 2: Calculate GPM (Gallons per Minute):
\( \text{GPM} = \frac{\text{HP} \times 3960 \times \text{Efficiency}}{\text{Head (ft)}} \)
Step 3: Convert GPM to CFS (Cubic Feet per Second):
\( \text{CFS} = \text{GPM} \times 0.002228009 \)
Combined Formula:
\( \text{CFS} = \frac{\text{HP} \times 3960 \times \text{Efficiency} \times 0.002228009}{\text{Head (ft)}} \)
Where:
- \( \text{HP} \): Horsepower, a unit of power.
- \( \text{Efficiency} \): Pump efficiency as a decimal (e.g., 0.85 for 85%).
- \( \text{Head} \): Total dynamic head in selected unit (cm, m, in, or ft), converted to feet.
- \( \text{GPM} \): Gallons per minute, an intermediate flow rate unit.
- \( \text{CFS} \): Cubic feet per second, a unit of volumetric flow rate.
- \( 0.002228009 \): Conversion factor (1 gallon = 0.133680556 ft³, divided by 60 seconds).
Enter the horsepower, efficiency, head value, and select the head unit to calculate the flow rate in GPM and CFS.
Using the HP to CFS Converter
This converter is designed for applications in fluid dynamics, pump design, and hydraulic engineering to convert horsepower to flow rate in CFS.
Input the horsepower (HP), efficiency (as a decimal), head value, and select the head unit (cm, m, in, or ft). The calculator will convert the head to feet and display the flow rate in both GPM and CFS.
Example: Convert 2 HP to CFS with 0.85 efficiency and 5000 cm head.
- Horsepower: \( 2 \, \text{HP} \), Efficiency: \( 0.85 \), Head: \( 5000 \, \text{cm} \)
- Head in feet: \( 5000 \times 0.0328084 = 164.042 \, \text{ft} \)
- GPM: \( \frac{2 \times 3960 \times 0.85}{164.042} = 41.029373 \, \text{GPM} \)
- CFS: \( 41.029373 \times 0.002228009 = 0.091419 \, \text{CFS} \)
- Result: \( 2 \, \text{HP} = 0.091419 \, \text{CFS} \)
Use this tool for accurate conversions in engineering and fluid flow calculations.
Common Conversion Table
The following table provides quick reference conversions for HP to CFS with Efficiency = 0.85 and Head = 50 ft (or equivalent in other units):
| HP |
Head |
GPM |
CFS |
| 1 |
50 ft |
67.32 |
0.149981 |
| 2 |
1524 cm |
134.64 |
0.299962 |
| 5 |
15.24 m |
336.60 |
0.749905 |
| 10 |
600 in |
673.20 |
1.499810 |
| 20 |
50 ft |
1346.40 |
2.999620 |
Use this table for quick lookups or to verify calculator results. Note: Head values are equivalent to 50 ft (1524 cm, 15.24 m, 600 in).
Common FAQ
Below are frequently asked questions about HP to CFS conversions:
- Q: What is the difference between GPM and CFS?
A: GPM (gallons per minute) measures flow rate in gallons, while CFS (cubic feet per second) measures flow in cubic feet. 1 CFS ≈ 448.831 GPM, and 1 GPM ≈ 0.002228009 CFS.
- Q: Why is efficiency needed in the calculation?
A: Efficiency accounts for energy losses in pumps or systems, expressed as a decimal (e.g., 0.85 for 85% efficiency).
- Q: What units can I use for head?
A: You can input head in centimeters (cm), meters (m), inches (in), or feet (ft). The calculator converts all inputs to feet for computation.
- Q: How accurate is this converter?
A: The converter uses precise conversion factors (e.g., 0.002228009 for GPM to CFS, 0.0328084 for cm to ft) and provides results rounded to 6 decimal places for accuracy.
- Q: Can negative values be used?
A: Negative HP or head values are not physically meaningful. Efficiency should be between 0 and 1. The calculator enforces positive head values.
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