Convert Watt to Metric Horsepower (W → PS)

Converting watts to metric horsepower is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in watts

   Start with the number of watts (W) you want to convert.
2. 2
   Multiply by 0.00136

   The conversion factor from W to PS is 0.00136. Multiply your value by this number.
3. 3
   Read the result in metric horsepower

   The result is your value in metric horsepower (PS).

Multiply the value in watts by 0.00136. For the reverse direction, multiply by 735.49875.

• ✓1 W = 1 J/s = 1 V × 1 A (for DC).
• ✓LED lighting: 10× more efficient than incandescent.
• ✓For home appliances, rating × hours used = kWh.

• ✗Confusing watts (power) with joules (energy).
• ✗Assuming "100 W bulb" for LED — old incandescent rating.
• ✗Mixing W with V or A — different quantities.

What is the Watt?

The watt is the SI unit of power, equal to one joule per second (1 W = 1 J/s). Named after Scottish engineer James Watt (1736–1819), whose improvements to the steam engine sparked the Industrial Revolution, the watt unifies mechanical, electrical, and thermal power. A typical LED bulb consumes 8–12 W to produce as much light as a 60-W incandescent bulb. Human resting metabolism is about 80–100 W of heat output, while peak athletic performance reaches 400–1,500 W (briefly). The watt is fundamental in electrical engineering: P = V × I (power = voltage × current). It relates to the kilowatt (1 kW = 1,000 W), the megawatt (1 MW = 10⁶ W), horsepower (1 hp ≈ 745.7 W), and the BTU per hour (1 W ≈ 3.412 BTU/h). Light bulb and appliance ratings, electric motor outputs, and audio amplifier specifications all use the watt as the base unit.

• Light-bulb and appliance ratings
• Scientific and engineering power specs
• Radio and electronics power

What is the Metric Horsepower?

The Pferdestärke (PS), also called metric horsepower or 'cheval vapeur' (CV) in French, equals exactly 735.49875 watts — about 1.4% smaller than mechanical horsepower. Defined as the power needed to lift 75 kg by 1 meter in 1 second under standard gravity, the PS is the European traditional power unit for car engines. German, French, Italian, and Japanese car manufacturers historically rated engines in PS, and the unit persists in marketing — '300 PS' sounds slightly higher than '300 hp' to consumers. EU regulations require power to be specified primarily in kW, with PS allowed as a secondary unit. The PS relates to the watt (1 PS ≈ 735.5 W), the kilowatt (1 PS ≈ 0.7355 kW), and the mechanical horsepower (1 PS ≈ 0.9863 hp). The slight difference between PS and hp is mostly imperceptible in casual use but noticeable in precise engineering specifications.

• European car and motorcycle ratings
• Italian and German engine specs
• Some European industrial equipment