Part 89: Side Note #10: Experience and Its Eight Thousand Formulae

Sides Notes 10: Experience and Its Eight Thousand Formulae

Wanna talk about how Pokemon gain experience and that? No? Well okay, but I'm gonna anyway... Every Pokemon has a set experience yield. Before Gen 5, this was a number between 20 (Magikarp) and 255 (Blissey) that is plugged into the much larger experience formula that we'll be going into later. Next, all Pokemon are divided into various experience groups that each have their own unique formula to determine how much experience a Pokemon needs to reach the next level. In Gen 1 and 2, there are four of these groups (Fast, Medium Fast, Medium Slow and Slow), whereas in Gen 3 on, there are 6 (the two new groups are Erratic and Fluctuating). To see how much you need to reach level 100, there's a nice graph here. The two new groups have some interesting properties, but we'll talk about them in a future LP maybe.

First up, there are fairly simple formulae on how much a Pokemon in a certain group need to get to the next level. The formulae are as follows, in the order of Fast, Medium Fast, Medium Slow and Slow, with n being the current level.









The Fast formula is, indeed, the fastest, with only 800,000 points needed to get to level 100. The group consists of mostly Normal types. The Medium Fast is the simplest of the formulae, needing 1 million, however, it's actually a slower growth than Medium Slow until around level 67. That's maths for ya. This is the most common experience group. Medium Slow has one hell of an equation and requires 1,059,860 exp to reach level 100 and is the second largest group. Now because of its funky equation, the inflection point (where the graph line has a curving point) is at level 4, instead of level 0, it means you need more experience to get from level 2 to 3, then it does to get from 4 to 5. This also causes the experience underflow glitch in Gens 1 and 2, which we'll talk about in a moment. Finally, the Slow group requires 1,250,000 exp to reach level 100 and contains a lot of rare and powerful Pokemon.

So, the experience underflow glitch is because of how the graph works for level 1 Medium Slow Pokemon. They technically have -54 experience, but since the game doesn't recognize negative numbers, it instead interprets it as 16,777,162 instead. So when a Pokemon in that situation gains 53 experience or less in a battle, it immediately jumps from level 1 to 100 as the game determines its level based on how much experience it has. Obviously, you can't find any legitimate level 1 Pokemon in these games, so that explains why this glitch wasn't found. It was fixed in Gen 3, since those games use a lookup table instead of a formula.

Alright, it's time to show how the game works out how much experience you get when you beat a Pokemon. The formula used is in every generation but 5, which instead scales things depending on the levels of the Pokemon in battle. However, out of the notation used, f, p and v are not factors in Gen 2, since those bonuses (Pass Powers, Amie Affection and Past Evolution Level) don't exist yet.



OKAY, let's break this bad boy down. First, a is equal to 1 if the fainted Pokemon is wild, or 1.5 if the fainted Pokemon is owned by a trainer; t is 1 if the winning Pokemon has the same OT as the trainer, or 1.5 if it was obtained in a trade (and thus has a different OT); b is the base experience yield that changes depending on the species; e is 1.5 if the Pokemon is holding a Lucky Egg, or 1 otherwise and L is the level of the fainted Pokemon. The last notation, s, relates to the amount of Pokemon that battled against the fainted Pokemon, which also relates to the Exp. Share, or the Exp. All.

With the Exp. All, if it's not in the Bag, then s equals the number of Pokemon that participated in battle and did not faint. If it is in the Bag, then s is twice the number of Pokemon that participated and have not fainted in order to calculate the experience of the Pokemon that participated. Take that number and multiply it by the number of Pokemon in the party when calculating what the Exp. All gives out. Similarly, the Exp. Share does the same function, but the Pokemon holding the item gains half of the experience regardless, or split between how many in the party are holding an Exp. Share, as you can obtain multiple. Fun fact, in Gen 1, if you beat a level 2 Pokemon with the Exp. All, the experience given to the rest of the party will be 0. Cool.

Phew, that was a lot of words and mathematics, but even something as seemingly simple as getting experience in battle can be a pretty long process with a number of factors. It does show how much effort Game Freak puts into this sort of stuff.