Question · Power, in numbers
What is horsepower?
Horsepower is a unit of power, a measure of how fast work is done, traditionally defined as around 550 foot-pounds of work per second.
Horsepower measures power, which in engineering terms simply means the rate at which work gets done — not how much force is involved, but how quickly that force can act. The imperial definition, dating back to James Watt's original comparison against a working horse, sets one horsepower at roughly 550 foot-pounds of work per second. It's a unit, in other words, not a single fixed thing every engine has more or less of.
Car specs quote it in a few slightly different flavours depending on where and how it's measured, which is why the same engine can show up with more than one number attached. It's closely tied to BHP, which specifies one particular way of measuring it. Buying for someone who'll happily explain that difference at length? Car gifts for men is built with exactly that person in mind.
Written by Craig Fearn, Petrol & Ink.