What is the difference between hp and PS?

hp (mechanical horsepower) equals 745.7 watts and originated from James Watt's measurement of horse power. PS (Pferdestärke, metric horsepower) equals 735.5 watts and is defined as lifting 75 kgf one meter in one second. PS is used in Europe and Japan, while hp is standard in the US and UK.

How to convert kW to hp?

Divide the power in kilowatts by 0.7457 to get mechanical horsepower. For example, 10 kW = 10 / 0.7457 = 13.41 hp. Alternatively, multiply kW by 1.341 to get hp.

BTU/h (British Thermal Units per hour) is a unit of power commonly used in HVAC and heating applications. 1 BTU/h = 0.000293071 kW. Air conditioners and heaters are often rated in BTU/h.

How does power relate to torque?

Power equals torque multiplied by angular velocity. In practical terms: P (kW) = T (Nm) × n (RPM) / 9549. This means the same power can be achieved with high torque at low speed or low torque at high speed.

Is electric hp different from mechanical hp?

Yes. Electric horsepower is defined as exactly 746 watts, while mechanical horsepower is 745.69987 watts. The difference is negligible (0.04%) and in practice they are used interchangeably. This calculator uses the mechanical hp value (0.7457 kW).

Free Engineering Tool

Power Unit Converter

Convert between all common engineering power units instantly. Enter a value in any unit and see all conversions simultaneously.

This calculator was developed and verified by the Vibromera engineering team, makers of the Balanset portable balancing instruments.

kW ↔ hp PS ↔ BTU/h Nm × RPM

Power Value

Input Unit

Torque (Nm)

Speed (RPM)

Quick presets

All Conversions

Kilowatts

—

Watts

—

Mechanical Horsepower

—

Metric Horsepower (PS)

—

BTU per Hour

—

Foot-Pound-Force per Second

—

Kilocalories per Hour

—

Nm × RPM Equivalent

—

Power from Torque

When torque and rotational speed are known, power is calculated as:

P — power (kW)
T — torque (Nm)
n — rotational speed (RPM)

Conversion Factors to kW

Unit	Symbol	× Factor = kW	Exact Value
Watt	W	÷ 1000	1 W = 0.001 kW
Mechanical Horsepower	hp	× 0.7457	1 hp = 745.69987 W
Metric Horsepower	PS	× 0.7355	1 PS = 735.49875 W
BTU per Hour	BTU/h	× 0.000293071	1 BTU/h = 0.293071 W
Foot-Pound-Force/s	ft·lbf/s	× 0.001355818	1 ft·lbf/s = 1.355818 W
Kilocalorie per Hour	kcal/h	× 0.001163	1 kcal/h = 1.163 W

Practical Example

Example — Convert 10 hp to other units

Given: 10 hp (mechanical)

kW = 10 × 0.7457 = 7.457 kW

W = 7457 W

PS = 7.457 / 0.7355 = 10.14 PS

BTU/h = 7.457 / 0.000293071 = 25,436 BTU/h

ℹ️ Note: The difference between hp and PS is only ~1.4%. 1 hp = 1.01387 PS. In many practical contexts they are used interchangeably, but for precise engineering work, use the correct conversion.