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How do you convert amps to horsepower?



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Amps or A = Ampere is a unit for measuring electric intensity (I). Horsepower (= HP) is a unit for measuring the power (P) of an engine

So for example: P=200 HP and I=5.2 A

Those two are totally different and irrelevant to each other.


Not entirely true. Amps are a factor in calculating power, and so can be used to determine horsepower, but only when other factors are present.

Given other factors, you can find the horsepower. The easiest way is to determine watts by multiplying amps X volts. Next multiply watts by .00134 and you have horsepower.

If: amps (A)= 20 and volts (V)=120 then

A X V =2400 watts (W)

2400 watts X .00134 = 3.216 horsepower


To add a further wrinkle:

Horsepower is a measurement of OUTPUT power

Amps generally refers to the flow of current (not intensity as stated above - that is voltage) which is an INPUT of an electric motor

So to accurately compute how much horsepower an electric motor will PRODUCE you need to know the efficiency of that motor. Electric motors tend to be very efficient but not quite 100%.

So, multiply efficiency by the theoretical hp using the formula above to get your final answer.


Horsepower formulas;

Single phase HP = I x E x %eff x pf/746 (%eff = efficiency of the motor), (pf = power factor)

Three phase HP = I x E x 1.73 x %eff x pf/746 (%eff = efficiency of the motor), (pf = power factor)


What none of the above answers directly point out that horsepower is simply the Imperial Unit of measurement for power, in the same way that the watt is the SI unit for power.