ELI5: What’s the difference between horsepower and torque?

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To put it in the immortal words of Jeremy Clarkson: Horsepower is how fast you hit the wall. Torque is how far you take the wall with you


Horsepower is torque x speed. Easiest way to understand is to look at what torque fails to convey with a simple practical example I want to lift 1 pound at the end of a rope, so I need to buy a motor to do that. I buy a 1 ft pound torque motor for $100. I if I put a 1 foot radius pulley on it I can lift 1 pound. Great. Job done right? Well, another person sells a motor with 1 ft pound torque for only $10, was I ripped off? They can both lift the weight according to torque. Well this $10 motor spins at 1RPM and the $100 motor spins at 10RPM. Which means they lift at 6.2 feet per minute and 62 feet per minute respectively. Since HP is basically torque x speed, just looking at the horsepower would have told you the one motor was superior. The $100 motor has 10x the HP which is reflected in the fact it can either lift 10x the speed or 10x the weight at the same speed as the lower HP motor. It’s easy to tell here because we used simple units, but if the units were more complicated you would need to do a lot of math to figure all this out, or you could just look at the horsepower.


Torque is how hard you twist. Horsepower is how fast you twist hard. Eli7 version: Horsepower is literally torque * speed Horsepower = Torque x RPM / 5,252 Extra credit: The 5,252 factor is there only so you don’t end up with an ungodly large number. It’s also the reason why horsepower and torque curves always cross at 5,252.


Torque is the fancy way of saying leverage.There are two ways to increase leverage. Increase the force… *grunts*….or increase the distance at which you act… *smart.* Either can create an equivalent amount of… “spinnification” of a given mass. Torque is “work” in a circle, which is calculated by Force X Distance. How much force did I apply over that distance? Power is “I did a lot of torque fast” or “A little torque slow.” Power is a rate (as in “a number of things per second.”) A high torque with a small light gear and you spin really really fast. The same torque with a way way bigger gear and you’ll spin slower. How much torque can I apply per second? That’s power. (Note: You don’t get objects to move unless you apply a force per time, so torque, power, forces, energy usage, energy usage per time, etc., all come in a great big package with conjoined numbers and units) Examples with the same amount of Power: I could apply a low torque for a much longer time to get a heavy train moving. I could apply the same amount of torque to a hotwheels for a millisecond and shoot it to the sun.


Torque is the maximum amount of rotational force an engine can generate. This is analogue to how hard you can screw a nut (pun unintended) using a wrench. Power is work applied per time e.g. how fast the engine can apply this force / how fast you can screw the nut with the same wrench applying the same amount of rotational force to it.