By definition, 1 horsepower in electrical machinery is defined as 746 watts. The calculator presented above uses this definition. Dependant on the application, the calculator may suffice for other applications as well. Mechanical horsepower is often rounded from 745.699872 watts per horsepower to 746 watts. For other purposes, industries and countries, this calculator may not fulfill the needs of the user. The user of the calculator is encouraged to research further to understand whether the calculator is suitable for his or her purpose.

It should be noted that the very definition of what constitutes one horsepower has historically left unease in the scientific community. The development of machines that performed work opened an opportunity to define a standard of power that could be applied to these machines. However, defining power in terms of how much work a single horse could muster called for much subjective judgement. Sound math on argueable assumptions left room for a more accurate and repeatable standard. Today, science and most countries have abandoned "horsepower" as a power standard in favor of the more accurately defined "watt". "Horsepower" is still used largely in the automotive industry. It is, perhaps, a term the general populace can more easily assimilate without knowing the abstractive mathematical formulations that define it.