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.