What does "BHP" stand for in cars?

In cars, "BHP" stands for brake horsepower, also called shaft or delivered horsepower. It is the actual power output of a vehicle engine before the loss in power caused by the gearbox, water pump, generator, differential and other auxiliaries.

Brake horsepower is measured at the output shaft of the vehicle engine, and due to power losses, it differs from the actual horsepower delivered to the driving machinery. The mechanical efficiency of an engine is determined by calculating the ratio between BHP and indicated horsepower, which is the measure of power that the engine would deliver in the absence of frictional losses.