The capacity of jet engines is measured in thrust How thrust will be converted to Horse power?

Theoretically, thrust cannot be converted into horsepower because the latter is simply a form of electric energy, like watts. Thrust is a direct force (generally created by an engine) as opposed to horsepower, which is simply the potential to do 'work.'

Answer:

A standard rule of thumb (very approximate) is that 1 HP is equivalent to 2.6 lb of thrust when static at sea level. This will vary with the efficiency of the propeller at the very least, as well as the gearbox transferring power to the propeller.

Unfortunately the question becomes more difficult to answer when considering flight conditions - a propeller's efficiency drops off with speed while a jet engine's increases (in broad strokes).

The effects of altitude (and subsequent air density) must also be taken into consideration.

When I was in aviation trade school, we learned to use the thrust formula to switch between thrust and bhp. If you google "turbine thrust formula", you'll get the particulars. It's not a particularly useful calculation so it doesn't get used very often. You'll need to familiarize yourself with the equation's variables and how to apply them correctly. Once you understand the formula and what you're measuring, it's just a matter of plugging in the right values.