In what gens do the amount of EVs a Pokémon can hold in 1 stat differ?

So, I’ve heard a few times on sites and videos that explain EVs that a Pokémon can hold up to 252 EVs in one stat. I then checked another source, but this time it said a Pokémon can have a maximum of 255 EVs in one stat, which then got me confused. I looked it up, but it only said, “in previous generations” that they differed from 252 and 255. It never said the specific. Gens. So in what gens do maximum EVs in one stat differ?

Pleaselog inorregisterto add a comment.

Ever since Gen 3, when the current system of EVs was put in place,the maximum has always been 255. The reason why some people say the cap is 252 is because that’s the highest value that matters. Every 4 EVs gained, rounded down, will boost the stat by 1 point at Lv 100. Even though the actual cap is 255, those last three EVs will be ignored, like this:

252 EVs / 4 =63 extra points at Lv 100.255 EVs / 4 = 63.75, which the game will round down to63 extra points at Lv 100, same as 252.

In Generations I and II, effort points given are equal to the base stats of the defeated Pokémon species.The Pokémon data structure contains two EV bytes for each of the five stats (HP, Attack, Defense, Speed and Special), starting at zero when caught and with a maximum EV of 65535 for each stat.

Starting Generation 3, each stat can have up to 255 EVs.sourceThe reason why some people say the max is 252 EVs is because a Pokemon needs at least 4 EVs to increase a stat. Because the difference between 255 and 252 is less than 4, 252 EVs has the exact same effect as 255 EVs. If you treat the max as 255, then you have 1 EV left after maxing two stats. You can’t do anything with 1 EV. If you treat the max as 252, you can max two stats and have 6 remaining EVs to raise a third stat by 1.