When do you need more torque? How much horsepower do you need? And how do horsepower and torque relate?

Horsepower and torque are two of the most important metrics when it comes to your vehicle. These numbers tell you a lot about the vehicle you're going to buy, and manufacturers constantly strive to outgun their competition with higher horsepower and torque figures.

Pickup trucks have increasingly ridiculous torque figures, and sports cars' horsepower numbers seem to climb higher every year.

But what exactly are horsepower and torque, and how are they different?

First things first, what is torque? Well, in physical terms, torque can be defined as a rotational force. When you push in a straight line, you're applying linear force on that object. In turn, when you open a door handle, you're still applying a force, but it's a rotational force around an axis. This same phenomenon applies when using a wrench to tighten a bolt; you're applying rotational force. When tightening a bolt, two factors will influence how much torque is being applied to the bolt.

Because torque is equal to length multiplied by force, these two factors will be the length of the wrench and the amount of force you're applying to the wrench. Torque is measured in Newton-meters or lb-ft, and when you analyze the definition of torque, these units start to become less confusing. Going back to the bolt analogy, imagine you're applying one lb-ft of torque to the bolt. This can be visualized as using a wrench with one foot of length from the bolt to your arm and then applying one pound of force to the end of the wrench.

This produces one ft-lb of torque applied to the bolt. This rotational force is essential to cars, both gasoline and electric. In a vehicle, the engine (or electric motor) is responsible for producing this rotational force, which is transferred through the driveshaft. Without the rotational force produced by your vehicle's engine, or electric motors, the car wouldn't move an inch. Of course, this power has to be routed through transmissions and differentials, but in essence, the torque produced by your vehicle's power plant is what allows movement.

Torque can be manipulated through gearing to multiply it. Off-road vehicles also use a low-range transfer case which multiplies the torque from the engine into a much greater amount, allowing off-road vehicles to climb steep hills and dig themselves out of tough spots. This is also why you feel a sudden kick when accelerating an electric vehicle from a complete stop because the electric motor's torque is instantly available. In gasoline engines, you would have to wait for the peak of the torque curve to occur, which might be higher up in the rev range.

When we were discussing torque, time was irrelevant because the measurement only considers the amount of torque (or rotational force) the engine produces as combustion pushes down on the pistons. In terms of horsepower, we can think of the power an engine makes as the engine's ability to apply torque over a specified amount of time.

There's a formula for calculating horsepower, which goes like this: horsepower = T * RPM / 5252.

Confused? Don't worry. The T stands for torque (which we're already familiar with as the rotational force the engine produces), and the RPM is revolutions per minute. Likewise, don't worry about the 5252, as it's a constant, and if you've ever taken a physics course, you'll notice constants are the scotch tape that holds formulas together.

As you can tell from the RPM variable, horsepower is intricately tied to time. From the formula, we can see that if you want your car to put out more horsepower, you need to increment the torque (or the speed at which the engine turns). One theoretical way to increment torque in a gasoline engine would be to increase the amount of force (combustion) that pushes down on the piston, perhaps using forced induction like a turbocharger.

Calculating engine horsepower and torque isn't as easy as calibrating your torque wrench, but you can use a dyno to measure your vehicle's torque and horsepower figures in informative graphs.

High horsepower is super beneficial for lots of things. If you want to achieve a high top speed, you need a car with a higher horsepower figure. If you want to get the best acceleration figures possible, horsepower is also your ticket. Many people might say that weight reduction is super important, and it's true, but horsepower is king in today's automotive market.

Electric cars are some of the heaviest vehicles for sale, but performance EVs make up for their heaviness with extremely powerful engines that make power across the entire rev range. Cars that obliterate competitions where high-speed is the priority are always high-horsepower vehicles. Some of these cars can make upwards of 2,000 horsepower.

If you've ever seen pickup truck commercials, you know that they're all about that torque. There are heavy-duty pickup trucks that produce over 1,000 lb-ft of torque, which is absolutely insane. Some EV pickup trucks also produce insane torque figures. These pickup trucks have so much torque because torque is very beneficial when carrying heavy loads, especially if the torque is available lower down in the rev range.

Imagine carrying a huge trailer up a hill with an engine that produces all of its torque way up in the rev range—not a very pleasant experience. The more torque an engine has, the easier time the vehicle will have moving off the line, even when carrying a heavy load.

Decent amounts of torque down low also allow a vehicle to feel peppy and responsive versus a vehicle that feels lethargic in the lower RPMs. In the case of EVs, they feel so powerful because electric motors instantly produce their max torque, and there's no waiting like with gasoline engines.

At the end of the day, both torque and horsepower are important for a vehicle's daily functioning. In an ideal scenario, if you're not someone that needs a utility vehicle, like a pickup truck, having a harmonious blend of torque and horsepower is best.

Alex is a major car nerd who loves programming, writing and playing the piano. He graduated with a bachelor's in Computer Science and currently enjoys freelance writing full-time.

Join our newsletter for tech tips, reviews, free ebooks, and exclusive deals!