HP (short for Hit Points) is one of the six visible stats in the Pokémon main series games. It is a value that determines how much damage a Pokémon can receive. When a Pokémon's HP is completely down to 0, the Pokémon will faint. HP is the most frequently affected stat of them all, as depleting HP is the key factor in winning a battle. There are several ways to replenish a Pokémon's HP such as using items like Potions or in-battle moves like Rest or Synthesis. The average base HP for a Pokémon is 68, while the average base HP for a fully evolved Pokémon is 80.
HP is depicted as a long, horizontal bar that changes color according to how much HP the Pokémon has left along with numerical values showing the current and total HP. When a Pokémon's HP is full or above 50%, the bar will appear green. Below 50% but above 20% will cause the bar to appear yellow, while below 20% with the exception of 0% will cause it to appear red.
Prior to Generation V, likely due to mistakes in programming, the warning colors would kick in considerably sooner than the simple, round numbers of 50% and 20%. For example, in Generation I, the color of the HP bar was based on the number of pixels remaining on the HP bar, causing it to go yellow starting at 56% rather than 50%. In Generation IV, the HP bar turned yellow at 52.1% and red at 20.8%. This meant that 53/105 and 54/105 were erroneously displayed as yellow even though these fractions are bigger than half. From Generation V onward, this was fixed so that the HP bar turns yellow and red at exactly the intended percentages, so for example, 52/105 is displayed as yellow and 53/105 is displayed as green.
Determination of a Pokémon's HP stat
A Pokémon's total HP stat is calculated using a formula, invisible in the games but can be found within the program code of the games. The HP stat is the only stat whose value does not depend on the individual Pokémon's nature. Disregarding individual values and effort values, the HP stat is equal to 110 plus twice the species' base HP stat. Aside from Shedinja, whose HP is locked at a constant value of 1, a Pokémon's HP stat is calculated as follows:
This formula means that, with the obvious exception of Shedinja, the lowest total HP a Level 50 Pokémon can have is 60, and the lowest total HP a Level 100 Pokémon can have is 110.
Due to the parallels between this formula and the similar formula for the other five stats, the HP stat grows at the same rate as a non-HP stat that is 50 base points higher. For example, Venusaur's base HP stat of 80 is equivalent to a base stat of 130 on a non-HP stat, both having a base growth rate of 2.6 points per level. The HP stat will always be five points higher than the corresponding non-HP stat, however, due to having a constant term of "+10" instead of "+5".
Moves and abilities
As of June 2021, there are six moves that cost HP to use, one of which is conditional. The unconditional moves are Substitute, Clangorous Soul, Belly Drum, Mind Blown, and Steel Beam. Curse costs HP to use only if its user is a Ghost type.
The move Endure allows the user to survive any attack with at least 1 HP remaining. The Focus Sash has the same effect, except multi-strike moves such as Bullet Seed can continue hitting after activating the Focus Sash, so further hits will KO the Focus Sash holder. After this, 1 HP is treated internally as a normal value; for example, if a Pokémon at 1/320 regains HP from the effects of Grassy Terrain, it will be restored to 21/320 and not 20/320, nor will it stay at 1/320.
In spin-off games
Pokémon Mystery Dungeon series
In Pokémon Mystery Dungeon: Explorers of Time & Explorers of Darkness, boss Pokémon, such as the Groudon illusion at Steam Cave peak, tend to have inflated HP stats that are far higher than those of normal in-dungeon enemies, though the other stats remain the same. Aside from the Koffing and Zubat in Chapter 1 and the Drowzee in Chapter 3, all bosses have much higher HP stat than a Level 100 Kecleon, which has 340 HP, and no other in-dungeon enemy comes even close to that number. For recruitable bosses, such as Uxie and Regice, the Pokémon has an inflated HP stat for the duration of the battle, but once recruited, has a normal HP stat for its species and level.
If a Pokémon on the player's team falls below 25% of its maximum, it is considered to be at critically low health, indicated as "Low HP! Situation critical!" in the status screen. This status condition also causes Overgrow, Blaze, Torrent, and Swarm to double the damage when using moves of their respective types (the same types these abilities affect in the main series).
The dialogue text when talking to a team member in a dungeon depends on the percentage of its HP that it has when talked to.