Almost every car spec sheet leads with two numbers: horsepower and torque. They are related, but they describe different things, and knowing the difference helps you predict how a car will actually feel to drive.
Torque: the twisting force
Torque is a measure of rotational force — how hard the engine can twist the crankshaft. It is quoted in newton-metres (Nm) or pound-feet (lb-ft). One lb-ft is about 1.356 Nm, so an engine rated at 300 Nm produces roughly 221 lb-ft.
Torque is what you feel when you press the accelerator at low or medium speed: the shove in the back when pulling away from traffic lights, or the ability to overtake without changing down a gear. Engines with a lot of torque low in the rev range — turbocharged petrol engines, diesels and electric motors — tend to feel strong and relaxed in everyday driving.
Horsepower: how quickly work gets done
Horsepower is a measure of power, which is the rate at which the engine does work. Power combines torque with engine speed. In imperial units the relationship is simple:
horsepower = torque (lb-ft) × rpm ÷ 5,252
That formula explains a lot. An engine that keeps producing good torque at high rpm will make a big horsepower figure, because rpm multiplies the torque. Power is what determines how fast a car can ultimately accelerate at higher speeds and what top speed it can reach.
It also explains why horsepower and torque curves always cross at 5,252 rpm when plotted in hp and lb-ft on the same scale.
Peak figures only tell part of the story
Spec sheets usually quote peak values — the highest torque and the highest power the engine produces, each at a particular rpm. Two engines with the same peak horsepower can feel very different:
- A turbocharged engine may deliver its peak torque across a wide band from low revs, so it feels strong without being revved hard.
- A naturally aspirated engine often builds torque more gradually and makes its peak power near the top of the rev range, rewarding drivers who rev it out.
- An electric motor can deliver maximum torque from a standstill, which is why many EVs feel so quick when pulling away.
If a spec sheet lists the rpm at which peak torque arrives, a lower number usually means more usable everyday pull.
Units you will see: hp, bhp, PS and kW
- hp (mechanical horsepower) is common in the United States.
- bhp (brake horsepower) refers to power measured at the engine’s crankshaft; in practice it is used interchangeably with hp in many markets.
- PS (metric horsepower, from the German Pferdestärke) is slightly smaller: 1 PS ≈ 0.986 hp. A 150 PS engine is about 148 hp.
- kW (kilowatts) is the official SI unit used across Europe and much of the world. 1 kW ≈ 1.341 hp, and 1 hp ≈ 0.746 kW.
CarDetails.org lists both horsepower and kilowatts where available so you can compare across markets.
Weight matters as much as power
A powerful engine in a heavy car will not necessarily feel faster than a modest engine in a light one. A useful way to compare cars is the power-to-weight ratio: divide horsepower by curb weight. For example, 200 hp in a 1,400 kg car gives about 143 hp per tonne, while 250 hp in a 2,000 kg SUV gives 125 hp per tonne — so the smaller car may well be quicker despite having less power. Gearing, traction and aerodynamics also play a part, which is why the 0–60 mph time is a helpful real-world summary.
What should you look for?
- For daily driving and towing, prioritise torque — especially torque available at low rpm. Diesels, turbocharged petrols and EVs are strong here.
- For motorway overtaking and performance, horsepower and power-to-weight matter more.
- For a quick comparison, look at 0–60 mph (or 0–100 km/h) alongside power and weight rather than any single number.
Quick summary
- Torque is twisting force; it is what you feel when accelerating at everyday speeds.
- Horsepower is torque multiplied by engine speed; it governs acceleration at higher speeds and top speed.
- Peak figures do not show how the power is delivered — look at where in the rev range it arrives.
- Always consider weight: power-to-weight is a better guide to performance than power alone.
Want to see these numbers side by side? Look up any car or use the comparison tool to line up three models.