It's probably been asked, but I couldn't find it, and I don't really fancy working it out. I haven't done any maths for weeks. Is it like +25, is it percentage based or some other algorithm or something?

#10% increase/decrease

>A Pokémon's Nature usually affects the growth rate of two of its stats, ultimately increasing one of its stats by 10% and decreasing another by 10%

Bulbapedia

Each nature increases one of its stats by 10% and decreases one by 10% (by the time it reaches level 100).

Is that what you're looking for? If not I'll hide.

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