Power Points (abbreviated PP) are points that determine how many times a Pokémon can use an attack. An attack will have a limit of either 5, 10, 15, 20, 25, 30 or 40 PP. Each time a Pokémon uses an attack, the PP for that move usually goes down by 1 point, but there are acceptions.
Other effects that drain PP
The Ghost-Type move Spite will remove PP from the previously used attack. In past generations the amount of PP reduced varied from 2 to 5. In Generation V, Spite is set to reduce 4 PP from the last used attack.
Another Ghost-Type move has a different effect on a Pokémon's PP. If Grudge is used right before the user is fainted, the attack used prior to the user's fainting has its PP drained all the way to 0, rendering the attack unusable unless the PP is restored.
Should a Pokémon run out of PP on all four of its moves, it uses an attack called Struggle, which does damage but causes recoil damage as well.
The Ability Pressure doubles the amount of PP used per attack, draining 2 PP per attack instead of one. Attacks that have 1 PP left can still be used, but will still have 0 PP after that attack is used.
The PP of an attack can be increased by using a PP Up or a PP Max. The most that an Attack's PP can be increased is 60% of its original number; for example an attack like Ice Beam, which has 10 PP, can be increased to a maximum of 16 PP, and an attack like Hydro Cannon having 5 PP can be upgraded to a maximum to 8 PP.
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