HP
Hit Points, or HP for short, determine how much damage a Pokémon can receive before fainting. It is the most visible of the stats in battle, appearing both graphically (as a bar that is green, yellow, or red depending on how much HP is left) and as a current/total amount below the bar.
The average base HP stat is 68 for all Pokémon, and the average for all fully evolved Pokémon is 80.
If a Pokémon has more than half of its HP, its HP bar remains green. If the Pokémon has between one-fifth and half of its HP, the bar will turn yellow. If a Pokémon has less than one-fifth of its HP remaining, the bar will turn red.
The HP bar also affects the Pokémon's cry. If a Pokémon's HP bar is green, the player will hear the cry of the Pokémon in its normal sounding rate, but if the Pokémon has less than half of its HP remaining or has fainted, its cry will be lowered by a half-step to indicate its weakened state.