Three layers behind one number
The stats screen shows six values: HP, Attack, Defense, Sp. Atk, Sp. Def, and Speed. They look like something the game simply handed out, with nothing to discuss. In reality, each one is built from several independent ingredients: the species' base stat, IVs, EVs, nature, and the level that scales the whole thing. Until you know which ingredient does what, every difference between two Pokémon of the same species looks like pure chance.
Below I take these layers apart one at a time, then put them back together in one concrete example, with real numbers, step by step.
Base stats: what the species gets
Base stats belong to the species, not to the individual. Every Garchomp has a base Attack of 130 and a base Speed of 102. Every Blissey has a base HP of 255 and a base Defense of 10. These are exactly the numbers you see on the Pokédex pages, and they decide what a Pokémon is even suited for: a fast physical attacker or a slow special wall.
Base stats are fixed. You can't raise or lower them. Only evolution, a regional form, or Mega Evolution changes them, because each of those is technically a separate entry in the data. If you want to see how two species stack up side by side in every category, the quickest way is the comparison tool. Keep in mind that the base stat total (BST) is a rough guide, not a verdict. The list of Pokémon with the highest totals is dominated by Legendaries, but plenty of lower-tier creatures beat them in practice thanks to a better spread of those points, better typing, and better Abilities.
IVs: a random fingerprint
IVs (Individual Values) are six hidden numbers in the 0–31 range, one for each stat. They're rolled the moment the Pokémon comes into existence: when you encounter it in the grass, when it hatches from an Egg, when you receive it as a gift. From then on they never change. Leveling, training, and evolution have no effect on them.
That's why two Pikachu caught right next to each other aren't identical. One might have an Attack IV of 31, the other an IV of 0. At level 100 that works out to exactly 31 points of difference in that stat, which for a Pokémon with a base Attack of 55 is roughly a fifth of the whole value. At level 50, the standard for most competitive battles, the same gap is worth about 15 points.
IVs aren't displayed directly. Newer games do have the Judge, though, which describes them in words, from "No Good" up to "Best" for a value of 31. Once you unlock this feature, the rating appears as a chart in the Pokémon's summary, and it's the most convenient way to check without doing any math by hand.
One mechanical curiosity: in older generations, IVs determined the type and power of the move Hidden Power. That's why some breeders deliberately hunted for Pokémon with imperfect IVs.
EVs: the only layer you build yourself
EVs (Effort Values) are effort points a Pokémon earns for every opponent it defeats. They aren't random and they don't depend on the species you battle with. They depend on who you defeat. Each species gives out a fixed amount of EVs in a specific stat: defeating a Magikarp gives 1 Speed EV, defeating a Geodude gives 1 Defense EV, and stronger, fully evolved forms usually give 2 or 3 points.
There are two limits:
- 252 EVs at most in a single stat (older games allowed 255, but the extra did nothing anyway),
- 510 EVs in total across all six stats.
The conversion is simple: 4 EVs = 1 stat point at level 100. The maximum of 252 EVs therefore gives 63 points. In practice the 510 limit means you can max out two stats (252 + 252) and have 6 EVs left for a third. That's where the popular "252/252/4" spread you'll see in every team sheet comes from.
This is the most important layer, because it's entirely under your control and it's worth more than IVs. The difference between a Pokémon with 0 and 252 Attack EVs is 63 points; the difference between the worst and the best IV is 31. A wild-caught Pokémon you simply played through the story with has its EVs scattered randomly across every stat, which means they're wasted.
Natures: 25 ways to shift the emphasis
A nature is a trait assigned at random when a Pokémon comes into existence. There are 25 of them, and each one modifies two stats: it raises one by 10% and lowers another by 10%. HP is never affected; a nature can neither raise nor lower it.
Five natures (Hardy, Docile, Serious, Bashful, Quirky) raise and lower the same stat, so in practice they do nothing. These are the neutral natures. Here are the ones used most often:
| Nature | Raises (+10%) | Lowers (−10%) | Typical use |
|---|---|---|---|
| Adamant | Attack | Sp. Atk | physical attacker |
| Jolly | Speed | Sp. Atk | fast physical attacker |
| Modest | Sp. Atk | Attack | special attacker |
| Timid | Speed | Attack | fast special attacker |
| Bold | Defense | Attack | physical wall |
| Calm | Sp. Def | Attack | special wall |
| Careful | Sp. Def | Sp. Atk | support wall |
| Impish | Defense | Sp. Atk | physical counter wall |
| Hardy and 4 others | — | — | no effect (neutral) |
The rule for picking one is common sense: lower the stat you don't use anyway. A Pokémon that only uses physical moves loses nothing with Adamant, because its Special Attack is useless. The exception comes with moves like Foul Play, or with confusion damage, where the "dead" stat suddenly starts to matter.
The formula: how it all adds up to one number
For HP:
HP = [(2 × base + IV + EV/4) × level / 100] + level + 10
For the other five stats:
Stat = ([(2 × base + IV + EV/4) × level / 100] + 5) × nature
Here "nature" is 1.1 for the boosted stat, 0.9 for the lowered one, and 1.0 in every other case. The square brackets mean rounding down: the game drops fractions at each of these steps, including when it divides EVs by 4. That's why 250 EVs give exactly as many points as 252, but 252 is divisible by 4 and became the standard value.
Example: Garchomp at level 100
Take a Garchomp with an Adamant nature, perfect IVs (31), and an EV spread of 252 Attack, 252 Speed, 4 HP. Let's calculate Attack:
- Garchomp's base Attack is 130, so 2 × 130 = 260.
- Add the IV: 260 + 31 = 291.
- Add the EVs divided by 4: 252 / 4 = 63, so 291 + 63 = 354.
- Multiply by the level and divide by 100: 354 × 100 / 100 = 354.
- Add 5: 359.
- Multiply by the nature: 359 × 1.1 = 394.9, rounded down to 394.
Here's the full set of numbers for the same Pokémon:
| Stat | Base | IV | EV | Nature | Result (Lv. 100) |
|---|---|---|---|---|---|
| HP | 108 | 31 | 4 | — | 358 |
| Attack | 130 | 31 | 252 | ×1.1 | 394 |
| Defense | 95 | 31 | 0 | ×1.0 | 226 |
| Sp. Atk | 80 | 31 | 0 | ×0.9 | 176 |
| Sp. Def | 85 | 31 | 0 | ×1.0 | 206 |
| Speed | 102 | 31 | 252 | ×1.0 | 303 |
For comparison, the same Garchomp with no EVs and zero IVs would have 291 Attack instead of 394. That's more than a hundred points of difference for the identical species at the identical level, and it's exactly why people talk about IVs, EVs, and natures at all.
Look at Speed, too: if the same Pokémon had a Jolly nature instead of Adamant, it would have 333 Speed instead of 303, at the cost of Attack dropping from 394 to 359. It's the classic choice between hitting harder and moving one step ahead of your opponent.
Tools that let you fix things
- Hyper Training is the only way to "fix" IVs. It doesn't change their actual value; it tells the game to calculate the stat as if the IV were 31. It requires a Bottle Cap (one stat) or a Gold Bottle Cap (all stats) and a high enough level. The effect isn't passed on to offspring when breeding.
- Vitamins (HP Up, Protein, Iron, Calcium, Zinc, and Carbos) add EVs to their matching stats. In newer games you can use them to push a stat all the way to the 252 limit, which turns EV training into a matter of money rather than hours of battling.
- Power items (Power Weight, Power Bracer, Power Belt, Power Lens, Power Band, and Power Anklet) add a fixed amount of EVs to a chosen stat after every battle you win, no matter who you defeated. The cost is reduced Speed while the item is held. The Macho Brace, on the other hand, doubles all the EVs you earn.
- EV-reducing Berries (Pomeg, Kelpsy, Qualot, Hondew, Grepa, and Tamato) remove EVs from a specific stat. They're a lifesaver for a Pokémon you played through the story with and whose points are scattered at random: first you wipe them, then you train from scratch.
- Pokérus is a harmless "illness" that permanently doubles the EVs a Pokémon earns. If yours catches it, spread it to the rest of your team before it wears off.
When is any of this worth worrying about?
The honest answer: while playing through the story, almost never. Opponents controlled by the game have weak teams, and a level advantage plus sensible type matchups take care of everything. A Pokémon with average IVs, a random nature, and zero EVs will get through the campaign just fine. You'll gain a lot more by checking the type chart and choosing moves that hit weaknesses.
The picture flips completely in battles against other players. There, everyone plays at level 50 or 100, everyone has maxed EVs and near-perfect IVs, so those 63 points stop being a bonus and become the price of entry. Speed benchmarks matter most of all: a single point decides who attacks first, and that is often the whole battle.
In short: the base stats say what a Pokémon is. The nature decides which way you tilt it. EVs are the only part you actually build yourself. IVs are a lottery that newer games let you get around.
One last caveat: stats aren't everything. An Ability can change a Pokémon's role more than any EV spread. Huge Power doubles Attack, and Levitate wipes out its entire Ground-type weakness. Before you start counting points, check what your Pokémon comes with by default and compare candidates in the comparison tool. The numbers are only the second step.