Convert Volt-Ampere to Metric Horsepower (VA → PS)

Converting volt-amperes 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 volt-amperes

   Start with the number of volt-amperes (VA) you want to convert.
2. 2
   Multiply by 0.00136

   The conversion factor from VA 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 volt-amperes by 0.00136. For the reverse direction, multiply by 735.49875.

• ✓VA = V × A (RMS).
• ✓For purely resistive loads, VA = W.
• ✓For motors, computers: VA > W (power factor < 1).

• ✗Treating VA and W as identical — only true for resistive loads.
• ✗Buying UPS by W when VA rating is required.
• ✗Ignoring power factor in transformer sizing.

What is the Volt-Ampere?

The volt-ampere (VA) is the SI unit of apparent power in alternating-current (AC) electrical systems. Equal to volts times amperes, the VA represents the magnitude of power flowing in an AC circuit before accounting for the phase relationship between voltage and current. For purely resistive loads (incandescent bulbs, heaters), 1 VA = 1 W. For reactive loads (motors, transformers, fluorescent lights), the apparent power (VA) is larger than the real power (W) because of the phase shift — the ratio is the 'power factor.' Transformers, UPS units, and generators are rated in VA or kVA (kilo-VA) because they must handle the apparent power, not just the real power. A typical home UPS for a desktop computer is 600–1,500 VA. The VA relates to the watt (1 VA = 1 W only at unity power factor), the kilovolt-ampere (1 kVA = 1,000 VA), and the megavolt-ampere (1 MVA = 10⁶ VA — used in utility-scale transformers).

• Transformer sizing
• Uninterruptible power supply (UPS) ratings
• Generator capacity

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