Pokémon Red Version, Blue Version, and Yellow Version - Exp. Points
Whenever a Pokémon on the opposite side of the player faints in a battle against a wild Pokémon or an in-game Trainer, each Pokémon that participated in the battle against it gains Exp. Points (or experience points). The number of Exp. Points a Pokémon gains this way is based on a formula shown below. Each multiplication and division given is rounded down. Note that the formulas below can return 0.
Exp. Points = ((L*(G/(E*F)))/7))*X*Y
Stat Experience Gained = B/(E*F)
where:
- L = Defeated Pokémon’s level
- G = Base Experience for the defeated Pokémon’s original species
- X = If the battle is a Trainer battle, X=1.5; else 1.
- Y = If the participating Pokémon’s Trainer ID is different from the player’s, Y=1.5; else 1 ("[name] gained a boosted [value] Exp. Points!")
- E = Number of unfainted Pokémon that participated in the battle against the defeated Pokémon.
- F = If Exp. All is in the player’s pack, F=2; else 1.
- B = Race value (commonly called "base stat") for the defeated Pokémon’s current species.
A "participant" means each unfainted Pokémon (other than an Egg) in the player’s party who had seen the opposing Pokémon since the last time the opposing Pokémon entered the battle. A participant need not have used an attack against the Pokémon, but must merely have seen it. If a Pokémon faints at the same time as the opposing Pokémon, it doesn’t count as a participant. (In battles in which Exp. Points can be gained, if both teams have no Pokémon at the same time, it is considered a loss for the player.)
If Exp. All is in the player’s pack, the Pokémon earns Exp. Points in up to two stages: once if the Pokémon is a participant as defined above, and once more if it is an unfainted Pokémon regardless of whether it’s a participant (in which case E is equal to the number of Pokémon in the player’s party in the above formula.) Stat experience is earned in the same way.
When a Pokémon gains a level, its current HP is its new HP minus the HP lost before the level gain. The Pokémon automatically gains up to the new level identified by the new amount of Exp. Points, thus possibly preventing the Pokémon from learning moves that it normally would on levels skipped this way.
While a Pokémon is in the Day-Care, it will earn 1 Exp. Point for each step the player walks and will learn new moves as it gains levels; such moves, if the list is full, will overwrite older moves, starting from the top of the list. However, the Day-Care person won’t accept a Pokémon that has learned an HM move.