Growth is a factor that determines the relative size of Pokémon compared to other Pokémon of the same species. This factor is randomly generated when the Pokémon spawns and cannot be changed without using external NBT editors. It has no effect on gameplay besides aesthetics and hitboxes (i.e. no effect in battle). A Pokémon's growth can be looked up by examining its stats in the PokéChecker.
A Pokémon's size also grows as its level increases, but this factor is independent of the growth stat.
List of growths
The microscopic and ginormous growths cannot be found on wild Pokémon. They can only be obtained by breeding.
Breeding allows the two parent Pokémon to pass on their growths to their offspring. Growth inheritance is determined by the growth between the mother's and father's growths (e.g., ordinary is directly between runt and giant), with some random variance allowing the two growths directly next to the determined growth (using the previous example, small and huge growths would be possible as well). This slight variance in growth will occur even if both parents have the same growth.
Taking advantage of growth inheritance is the only way to obtain Pokémon that are microscopic or ginormous. This requires two Pokémon that are pygmy or two Pokémon that are enormous (respectively) to breed together. Each offspring from these Pokémon will having a ⅓ chance of inheriting these rare growths.
- "growthScaleModifier": How much growth affects Pokémon size.
Within NBT tags, growth is stored as a numerical ID. These numbers are only useful when editing Pokémon NBT data externally or when specifying growth with the /pokespawn and /pokegive commands.