Enter any two values (power, mass flow rate, and specific energy per unit mass) into the calculator to determine the missing variable.
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Lbs/Min to Hp Formula
There is no universal, one-step unit conversion from lb/min (a mass flow rate) to horsepower (power). To compute power from a mass flow rate, you must also know the specific energy (work/energy per unit mass) being added to or removed from the flow.
Hp = \frac{(Lbs/Min)\times SE}{33{,}000}Variables:
- Hp is the power in horsepower (mechanical hp).
- Lbs/Min is the mass flow rate in pounds per minute (lb/min).
- SE is the specific energy (work/energy per unit mass). In the formula above, SE must be in ft·lbf/lb (or converted to that unit).
- 33,000 is the conversion constant: 1 hp = 33,000 ft·lbf/min.
To calculate horsepower, multiply the mass flow rate by the specific energy per unit mass and divide by 33,000.
| Pounds per Minute (lb/min) | Horsepower (hp) |
|---|---|
| 0.5 | 0.151515 |
| 1 | 0.303030 |
| 2 | 0.606061 |
| 3 | 0.909091 |
| 5 | 1.515152 |
| 7.5 | 2.272727 |
| 10 | 3.030303 |
| 12.5 | 3.787879 |
| 15 | 4.545455 |
| 20 | 6.060606 |
| 25 | 7.575758 |
| 30 | 9.090909 |
| 40 | 12.121212 |
| 50 | 15.151515 |
| 60 | 18.181818 |
| 75 | 22.727273 |
| 100 | 30.303030 |
| 150 | 45.454545 |
| 200 | 60.606061 |
| 300 | 90.909091 |
| Formula: Hp = (lb/min × SE(ft·lbf/lb)) ÷ 33,000. Unit notes: 1 kW = 1.34102 hp; 1 kg/min = 2.20462 lb/min; 1 Btu/lb = 778.169 ft·lbf/lb; 1 kJ/kg ≈ 334.0 ft·lbf/lb. | |
What is Lbs/Min to Hp?
“Lbs/Min to Hp” is not a direct unit conversion. It is a calculation that determines power (hp) from a mass flow rate (lb/min) only when you also know the specific energy/work per unit mass associated with the process (for example, a known enthalpy change, specific work added by a pump/compressor, or energy extracted by a turbine).
How to Calculate Lbs/Min to Hp?
The following steps outline how to calculate horsepower from pounds per minute when the specific energy is known.
- Determine the mass flow rate (Lbs/Min).
- Determine the specific energy per unit mass (SE), and ensure it is in ft·lbf/lb (or convert it).
- Calculate the horsepower using: Hp = (Lbs/Min × SE) ÷ 33,000.
- After inserting the values and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Pounds per minute (Lbs/Min) = 100
Specific Energy (SE) = 10,000 ft·lbf/lb
Horsepower (Hp) = (100 × 10,000) ÷ 33,000 = 30.3030 hp