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What is bhp?

You may have come across the term ‘bhp’ while looking for your next car. What does it mean and why does it matter? Our guide explains.

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By Cazoo editorial team

The term bhp is an expression of a car’s power. At Cazoo we use bhp to describe the power from engines or electric motors on the cars we have available, and so do many car-related magazines, manufacturers and other sources of car information.

Understanding exactly what bhp is and why it matters can help you understand more about what a car will feel like to drive and whether it’ll meet your needs. Read on to find out everything you need to know.

What does bhp mean?

The letters bhp stand for brake horsepower, which is a unit of measurement to describe the amount of power a car’s engine or electric motor generates to move it.

Without getting too technical, a car with an engine burns petrol or diesel fuel, producing small explosions that are harnessed to spin a component called a crankshaft. It’s that spinning motion that generates the engine’s power. The crankshaft is connected to the wheels via the gearbox.

There are different types of automatic gearbox, but in most electric cars the power is transferred directly to the wheels without going through a gearbox.

Why does bhp matter?

A bhp figure gives you a strong indication of how quickly a car can accelerate and what it would feel like to drive. Generally speaking, the higher a car’s bhp, the quicker it will accelerate, although you do have to take a car’s weight into account. A heavy car with a high bhp figure may not accelerate as quickly as a lighter car with lower bhp.

How much power you need from a car depends on how you’ll use it. If you mostly drive around town, a car with lower bhp could work well for you because you won’t be going that fast. But if you do lots of long motorway journeys, a car with higher bhp will be able to maintain typical cruising speeds more easily and efficiently.

Many car models are available with different engine options, which have different levels of power. As a general rule, cars with more bhp will cost more to buy. More power often burns more fuel too, so cars with more bhp can cost you more to run.

What’s the difference between bhp and hp?

There are several units of measurement for power – bhp is just one. The metric unit is called hp (horsepower) and is often expressed as PS, which stands for ‘pferdestärke’, the German term for horsepower.

Why the reference to horses? In the early days of the steam engine, engineer James Watt was trying to persuade mine owners to buy his engines to replace the horses they used to lift heavy loads. He came up with the horsepower measurement, defined as equivalent to the energy expended by a horse lifting a 33,000-pound weight up a 1,000-foot mine shaft in one minute. Sounds complicated, but it showed that one of Watts’ engines could do the work of many horses.    

Many car manufacturers use hp or PS for their official power figures because they sell most cars in countries that use the metric system. However, many British car magazines, websites and retailers use the imperial bhp.

You might occasionally see the letters ‘CV’, particularly on French cars. It’s the same unit as hp or PS, and is short for ‘cheval-vapeur’, the French term for horsepower. Fun fact: the term translates literally to ‘steam horses’.

You should note that bhp and hp/PS/CV aren’t equal – 1hp is 0.986bhp. That’s why you might see conflicting power figures for the car you’re interested in. For example, Volkswagen gives a figure of 320PS for the Golf R. At Cazoo, we’d give a figure of 316bhp.

The difference between the two figures is a result of how bhp and hp are measured, which we’ll cover in the next section.  

How is bhp measured?

An engine’s power is measured using a machine called a dynamometer (or a dyno). Metric horsepower (hp) is measured at the crankshaft as it spins up to full speed, while bhp is measured by spinning the crankshaft up to full speed, then letting it naturally slow down to a dead stop. That factors in the effect of friction on the engine’s power. 

What’s a good amount of bhp?

What constitutes a ‘good’ amount of bhp depends on what type of car you’re interested in and how you’re going to use it. For instance, 100bhp is plenty if you have a fairly small car  and mostly drive around town. If you want a larger car, or drive on motorways a lot, you’ll probably want more, because extra power will make it much easier to accelerate up to higher speeds.

In general, small cars have up to around 120bhp and most family-size cars have 120-200bhp. Generally, anything more than 200bhp can reasonably be considered a high-performance car. Luxury cars also often have several hundred bhp because of their greater size and weight.

How do I find out my car’s bhp?

Cazoo gives bhp figures in the details of all the cars we have available. If you want to know the bhp of a car you already own, you can simply search for it online by its make, model and engine type.

Be aware, though, that many engines are available with different amounts of bhp, because manufacturers can tune them to different levels. Ford’s 1.0-litre EcoBoost petrol engine, for instance, is available with various levels of power from 95bhp to 155bhp. If your car has an engine like that, you can search by its registration number to pin down exactly how much bhp it has.

What’s the difference between bhp and torque?

Torque is a measurement of ‘work’ rather than power, given in imperial units of lb/ft (pounds-per-foot) or the metric Nm (Newton metre). To give an analogy, if power is how fast you can pedal on a bicycle, torque is how hard you can push down on the pedals.

It’s possible for an engine to generate high power and low torque, and vice versa. The ideal is an engine that generates a balance of both. Diesel engines and electric motors tend to generate more torque than petrol engines produce. 

Cars with an engine that has higher torque can feel more effortless to drive than cars with lower torque. For example, when accelerating from standstill at a set of traffic lights, a high-torque engine needs fewer revs to get up to speed, meaning the engine doesn’t feel like it’s working so hard.

It can also accelerate the car from, say, 50-70mph on the motorway more quickly and more easily than a car with less torque. That’s why diesel cars can be a better option if you do a lot of motorway driving – diesel engines’ greater torque makes it easier to maintain high speeds, giving better fuel economy and a more relaxing driving experience in the process.

High torque is also useful for larger cars, and if you regularly load your car with lots of people or stuff, or tow a trailer or caravan. In those cases, you’re asking the engine to do more work and so extra torque will help it do that work.      

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