Hidden Power deals damage, however its type varies for every Pokémon, depending on that Pokémon’s Individual Values (IVs). This makes it a useful move for coverage – giving the Pokémon a type of move they don’t normally have. Hidden Power can be any type except Normal or Fairy. It receives STAB if the user’s type matches the type given to Hidden Power. Individual Values are 6 hidden numbers (one for each stat) that are randomly generated upon encountering a Pokémon. It is not possible to find your exact IVs in-game. You can find the type of Hidden Power in-game by talking to a particular character who will state the type a Pokémon’s Hidden Power would be if it learned the move. They are located at: Veilstone Game Corner Prize Exchange in Platinum Celadon Game Corner Prize Exchange in HeartGold/SoulSilver Mistralton City Pokécenter in Black/White Pokémon World Tournament in Black 2/White 2 Anistar City, south-easternmost house in X/Y. It is also possible via elimination by using the move against different Pokémon, or against Kecleon, whose ability Color Change will tell you the type.
In Generations 2-5, the base power of Hidden Power ranges from 30-70, depending on the user’s IVs. The move will be boosted by the ability Technician only if its power for that Pokémon is 60 or below.