Motor kW to HP Calculator
Convert electric motor power from kilowatts (kW) to mechanical horsepower (HP) or metric horsepower (PS) instantly using standard electrical engineering conversion formulas.
Motor kW to HP Calculator
How to Use Motor kW to HP Calculator
Converting motor ratings from kilowatts to horsepower helps electrical design and maintenance engineers quickly size and select replacement motors, review electrical layouts, and match machinery from different countries. Standardizing mechanical power units is simple with our calculator. Follow this step-by-step method to perform the calculation:
- 1Enter motor power in kW. Input the rated nominal motor power in kilowatts (kW) as listed on the manufacturer's nameplate.
- 2Select horsepower type. Choose either Mechanical Horsepower (HP) for US/UK machinery or Metric Horsepower (PS) for European standards from the dropdown list.
- 3Click calculate. Click the Calculate button to run the conversion model.
- 4Read converted horsepower result. Review the main display for the converted value, along with the details grid showing the input value, selected type, and conversion factor.
- 5Use result for motor sizing and comparison. Apply this horsepower value to cross-check standard motor frame tables or replacement specifications.
This workflow enables fast engineering evaluations, minimizing errors when verifying motor ratings across global standards. To perform winding electrical analysis, you can also compute equivalent winding values using our motor kW to resistance calculator.
How to Calculate Motor kW to HP
Calculating motor power conversion is based on standard conversion factors defined by the relationship between the SI unit of power (watts) and the historical standards of mechanical and metric horsepower. Here are the formulas and explanations for each horsepower type:
Mechanical Horsepower (HP) Formula
Mechanical horsepower (also known as imperial horsepower) is defined as 550 foot-pounds per second, which equals exactly 745.699872 watts. To convert kilowatts to mechanical horsepower, divide the power in kW by 0.745699872 (or multiply by 1.34102209):
Metric Horsepower (PS) Formula
Metric horsepower (Pferdestärke or PS) is defined as the power required to raise a 75-kilogram mass by 1 meter in 1 second, which equals exactly 735.49875 watts. To convert kilowatts to metric horsepower, divide the power in kW by 0.73549875 (or multiply by 1.35962162):
Step-by-Step Engineering Worked Example
Let's convert a standard industrial motor rated at 15 kW to both mechanical horsepower (HP) and metric horsepower (PS):
1. Mechanical Horsepower Conversion:
Using the mechanical conversion formula:
Rounding to two decimal places, a 15 kW motor delivers 20.12 HP.
2. Metric Horsepower Conversion:
Using the metric conversion formula:
Rounding to two decimal places, a 15 kW motor delivers 20.39 PS.
Real-World Motor Application Example
Consider an industrial pump system imported from Europe that features a nameplate power rating of 15 kW. A facility technician in the United States needs to order a replacement motor from a domestic supplier who uses NEMA ratings in horsepower. By running the conversion, the technician finds the motor is equivalent to 20.12 HP. Since standard NEMA motor frame sizes are rounded, the technician selects a standard 20 HP motor for the application, confirming the replacement is mechanically and thermally compatible.
To verify the current drawn by a motor of this size, engineers often refer to standard tables or calculate current requirements directly. You can estimate starting current reduction ratios with the star-delta motor current calculator or find overall ratings using the motor nameplate calculator.
Motor kW to HP Chart
This reference table provides calculated conversion values for standard motor ratings from 0.5 kW to 132 kW. The values show exact conversions to both mechanical horsepower (HP) and metric horsepower (PS) rounded to two decimal places. For sizing recommendations, check the motor sizing calculator.
| Motor Power (kW) | Mechanical Horsepower (HP) | Metric Horsepower (PS) |
|---|---|---|
| 0.5 kW | 0.67 HP | 0.68 PS |
| 0.75 kW | 1.01 HP | 1.02 PS |
| 1.0 kW | 1.34 HP | 1.36 PS |
| 1.5 kW | 2.01 HP | 2.04 PS |
| 2.2 kW | 2.95 HP | 2.99 PS |
| 3.0 kW | 4.02 HP | 4.08 PS |
| 5.5 kW | 7.38 HP | 7.48 PS |
| 7.5 kW | 10.06 HP | 10.20 PS |
| 11.0 kW | 14.75 HP | 14.96 PS |
| 15.0 kW | 20.12 HP | 20.39 PS |
| 18.5 kW | 24.81 HP | 25.15 PS |
| 22.0 kW | 29.50 HP | 29.91 PS |
| 30.0 kW | 40.23 HP | 40.79 PS |
| 37.0 kW | 49.62 HP | 50.31 PS |
| 45.0 kW | 60.35 HP | 61.18 PS |
| 55.0 kW | 73.76 HP | 74.78 PS |
| 75.0 kW | 100.58 HP | 101.97 PS |
| 90.0 kW | 120.69 HP | 122.37 PS |
| 110.0 kW | 147.51 HP | 149.56 PS |
| 132.0 kW | 177.01 HP | 179.47 PS |
Note: All table values are calculated using precise conversions and rounded to two decimal places. In industrial settings, select the standard commercial size closest to your converted value.
Unit Standardization: SI vs. Imperial Sizing in Motor kW to HP
When working with Motor kW to HP calculations, using consistent physical units is vital. Small translation errors between SI Metric units (like millimeters, kilowatts, and meters) and Imperial units (like AWG wire, horsepower, and feet) can lead to serious sizing errors:
| Dimension | SI Metric Unit | Imperial Unit | Conversion Conversion Factor |
|---|---|---|---|
| Power | Kilowatts (kW) | Horsepower (HP) | 1 kW ≈ 1.341 HP |
| Length | Meters (m) | Feet (ft) | 1 m ≈ 3.2808 ft |
| Flow Rate | Cubic meters/hr (m³/h) | Gallons/minute (GPM) | 1 m³/h ≈ 4.403 GPM |
Always perform unit checks before installing physical components for Motor kW to HP to ensure they match equipment specification sheets.
Motor kW to HP Frequently Asked Questions
To convert motor power from kilowatts (kW) to horsepower (HP), you multiply the power in kW by the standard conversion factor. For mechanical horsepower (common in US/UK), the formula is HP = kW × 1.34102209. For metric horsepower (common in Europe, also known as PS), the formula is PS = kW × 1.35962162. This allows you to quickly compare nameplate ratings across different manufacturer standards.
HP stands for mechanical horsepower (approximately 745.7 watts) and is the standard unit used in the United States and United Kingdom. PS stands for Pferdestärke (metric horsepower, approximately 735.5 watts), widely used in Germany and continental Europe. Because metric horsepower (PS) is slightly smaller than mechanical horsepower (HP), a motor rated in PS will have a numerically higher value than in HP.
Kilowatts (kW) is the official SI unit for power, which is recognized globally by international standards such as the IEC (International Electrotechnical Commission). Using kW provides a unified scientific measurement of electrical and mechanical energy. While HP is still popular in NEMA markets (North America), modern nameplates frequently show both units to ensure worldwide compliance and ease of installation.
Yes, 1 horsepower (HP or PS) represents a smaller quantity of power than 1 kilowatt (kW). Specifically, 1 kW is equivalent to approximately 1.341 mechanical horsepower. Therefore, when converting a motor's power rating from kilowatts to horsepower, the numerical value in horsepower will always be higher than its rating in kilowatts (for example, a 15 kW motor converts to 20.12 HP).
Yes. The mechanical power output of an electric motor (whether rated in kW or HP) is a pure mechanical measurement of shaft work. It is independent of the electrical supply type. Therefore, this kW to HP conversion calculator works identically for single-phase, three-phase, and DC motors. You do not need to alter the calculation based on voltage or phase configuration.
The conversion factor depends on the horsepower standard being used. For mechanical (imperial) horsepower, the conversion factor is 1.34102209 (HP = kW × 1.34102209). For metric horsepower, the conversion factor is 1.35962162 (PS = kW × 1.35962162). These factors are derived from the physical definitions of a watt relative to foot-pounds per second and meter-kilograms per second.
A 15 kW electric motor is equivalent to approximately 20.12 mechanical horsepower (HP) or 20.39 metric horsepower (PS). You calculate this by multiplying 15 kW by the respective conversion factors (15 × 1.34102209 = 20.115 HP, and 15 × 1.35962162 = 20.394 PS). This is one of the most common standard motor sizes used in industrial pumping, ventilation, and fan applications.
A 75 kW motor is equivalent to approximately 100.58 mechanical horsepower (HP) or 101.97 metric horsepower (PS). In practice, a 75 kW motor is typically matched directly to a standard 100 HP NEMA frame rating when swapping motors between European (IEC) and North American (NEMA) machinery, as the minor difference is well within the motor's operating tolerance and service factor.