Horsepower is a common statistic for measuring the mechanical energy output of an engine. It is sometimes useful to convert that mechanical measure into its equivalent in electricity. Getting to amps and volts, however, requires a middle step. This is because watts, which are also used in the metric system, are the best match for horsepower.
Convert horsepower into kilowatts, which is a metric measurement of 1,000 watts. To do this, multiply the horsepower by 0.746. As an example, a 180-horsepower car engine converts to 134.28 kilowatts or 134,280 watts.
Convert watts to amps using the following formula: watts divided by volts equals amps. Note this requires you to know the voltage. Without it, you cannot determine amperage. Using the model and the standard U.S. household voltage of 110 volts, the equation is 134,280 watts/110 volts = 1,220.72 amps.
Convert watts to volts using the following formula: watts divided by amps equals volts. Note that you will need to know the amps to complete the equation. For example, suppose you're dealing with 10 amps: 134,280 watts/10 amps = 13,428 volts.
TL;DR (Too Long; Didn't Read)
Watts and horsepower are similar because they are both measurements of energy applied to work. Using plumbing as an analogy, amps are similar to gallons delivered per minute; volts are the water pressure in the pipes.
It is impossible to convert horsepower to either amps or volts if at least one of these numbers is not already known.