Two Pikachu at the same level can have different stats. Three hidden things cause it: a Nature, IVs and EVs. The Nature has its own page. This page covers the other two. Think of IVs as talent you are born with, and EVs as practice you do. For the whole formula, see base stats explained and the stats, IVs, EVs and Natures guide.
IVs: the talent you cannot train
An IV (individual value) is a number from 0 to 31, and every Pokémon has one for each of its six stats. Serebii says each point is worth one stat point at level 100. The game sets them when the Pokémon first appears, so two wild ones of the same species can differ. With six stats and 32 possible values each, there are 1,073,741,824 combinations in total, which is why finding a Pokémon with perfect IVs takes patience.
Hyper Training can lift a Pokémon's IVs in battle. Serebii's page on it, written for Sun and Moon, says a Bottle Cap raises one IV to the maximum and a Gold Bottle Cap raises all six. It is a surface change. The real IVs stay the same, so breeding and the move Hidden Power do not see the boost.
EVs: the practice you can plan
An EV (effort value) is a point you earn by defeating Pokémon. Every species gives a small reward in particular stats. Per Serebii, a Pokémon can hold 510 EVs in total and 252 in any one stat (255 before Generation 7). Every 4 EVs add 1 stat point at level 100, so 252 EVs add 63.
That is why 252 is the practical top. A 255 wastes 3 points, and 510 splits neatly into 252, 252 and 6 spare points. The usual training plan puts the two big piles in the two stats a Pokémon needs most.
Level matters too. At level 50, about half as many EV points show up as at level 100.
A worked example
Gengar has a base Speed of 110. Here is what that becomes. The level 100 results for the lowest and the highest case match Pokémon Database, which lists 202 and 350.
| Case | Level 50 | Level 100 |
|---|---|---|
| 0 IV, 0 EV, neutral Nature | 115 | 225 |
| 31 IV, 0 EV, neutral | 130 | 256 |
| 31 IV, 252 EV, neutral | 162 | 319 |
| 31 IV, 252 EV, Nature that raises Speed | 178 | 350 |
| 0 IV, 0 EV, Nature that lowers Speed | 103 | 202 |
The first row is the worst case, with no talent and no training. The jump from row 1 to row 3 is 94 points at level 100, and a good Nature adds another 31. The same Pokémon at level 50 gains less from EVs, so check the level before you plan.
Which Pokémon give EVs
Our data covers all 1,025 Pokémon. Each gives between 1 and 3 points for a defeat, and 3 is the top. This table counts the species that give points in each stat.
| Stat | Species that give points in it | Give 3 points in it |
|---|---|---|
| HP | 131 | 30 |
| Attack | 297 | 62 |
| Defense | 168 | 19 |
| Sp. Atk | 197 | 57 |
| Sp. Def | 128 | 21 |
| Speed | 199 | 22 |
Attack is the most common reward, and Special Defense and HP are the rarest. The species in the third column give the full 3 points, so they are the best ones to defeat when you train. Here are the first ten of each.
| Stat | Species giving 3 points (first ten by Pokédex number) |
|---|---|
| HP | Nidoqueen, Clefable, Wigglytuff, Mew, Azumarill, Blissey, Celebi, Slaking, Exploud, Walrein and 20 more |
| Attack | Nidoking, Machamp, Victreebel, Dragonite, Tyranitar, Blaziken, Swampert, Shiftry, Salamence, Groudon and 52 more |
| Defense | Poliwrath, Golem, Aggron, Metagross, Regirock, Klinklang, Cobalion, Chesnaught, Kommo-o, Stakataka and 9 more |
| Sp. Atk | Charizard, Vileplume, Alakazam, Gengar, Zapdos, Moltres, Mewtwo, Typhlosion, Ampharos, Beautifly and 47 more |
| Sp. Def | Blastoise, Articuno, Bellossom, Politoed, Lugia, Ho-Oh, Dustox, Ludicolo, Regice, Latias and 11 more |
| Speed | Pidgeot, Raichu, Crobat, Jumpluff, Sceptile, Serperior, Scolipede, Greninja, Talonflame, Tapu Koko and 12 more |
There is a clear pattern by stage. First stages average about 1.6 points, middle stages about 2.0 and third stages exactly 3. Look at a few lines:
| Line | EV yield by stage |
|---|---|
| Chansey → Blissey | 2 HP → 3 HP |
| Gastly → Haunter → Gengar | 1 Sp. Atk → 2 Sp. Atk → 3 Sp. Atk |
| Machop → Machoke → Machamp | 1 Attack → 2 Attack → 3 Attack |
| Dratini → Dragonair → Dragonite | 1 Attack → 2 Attack → 3 Attack |
Blissey gives 3 HP to the Pokémon that defeats it, and Chansey gives 2. Legendary and Mythical Pokémon average about 2.9 points, so most of them give the full 3. Mewtwo gives 3 Special Attack. Using Pokémon Database, we checked Blissey, Chansey, Mewtwo, Pikachu and Gengar against our numbers, and all matched.
Not every game uses them
- Pokémon Legends: Arceus has neither EVs nor IVs in the stat maths. Serebii says each stat has an Effort Level from 0 to 10, and Grit items raise it.
- Let's Go, Pikachu! and Let's Go, Eevee! keep IVs but replace EVs with Awakening Values. Per Serebii, each gives 1 stat point whatever the level, up to 200 per stat, and Candy raises them.
Putting it to use
If you only play through the story, you can ignore all of this. If you want to train a team, look at the stat screen, pick a Nature you like, and spread EVs over the stats a Pokémon uses. To start, pick a Pokémon from the third-stage lists above and defeat a few dozen wild Pokémon that give its best stat. Count carefully, because 84 defeats of 3-point Pokémon fill one stat to 252 with no help from items.