Effort Values, or EVs for short, are numerical values contributing to a Pokémon's stats tremendously as they increase their power level manifold. A Pokémon earns said EVs by defeating another Pokémon in a battle that usually rewards experience. Thus, every encounter that awards experience will award Effort Values – based on the bested Pokémon's species.
Furthermore, capturing a Pokémon will offer you a clean slate to work with as newly captured Pokémon have no EVs allocated yet. Therefore, due to these Effort Values, trained Pokémon are usually more powerful than untrained or wild Pokémon, even when they are on the same level.
Currently, as of Gen 8, a Pokémon can obtain up to 510 EVs in total. Of these 510 total EVs, each stat can only allocate up to 252 EVs at max. This stat allocation means that you could theoretically max out two stats and still have 6 EVs left to put wherever you want or spread out all EVs evenly, creating a "more rounded and versatile" Pokémon.
Moreover, every 4 EVs gained in a stat will add a single stat point to your Pokémon's stat attribution, depending on the stats' EVs gained (4 HP EVs will increase your Pokémon's HP by 1). This stat increase means that when your Pokémon acquires a total of 510 EVs, making it a "Fully Trained Pokémon," will net it an overall stat increase of 63 stat points.
Pokémon gaining experience through holding an Exp. Share item will also receive Effort Values based on the opponent's EV yield. However, while the Pokémon holding the Exp. Share item will receive an EV bonus when affected by Pokérus, it will not get the benefits of an EV-enhancing item or condition the Pokémon in battle has.
As the name implies, Pokérus is a virus for Pokémon introduced in Generation 2. But, rather than being harmful, it is beneficial to your Pokémon and its EV training. Let me explain:
There is a small chance (approximately 1 in 21.845) that your Pokémon catches Pokérus after a battle concludes. Once infected, its newly earned Effort Values will double until the sick Pokémon recovers. In most games, a small icon will appear in the Pokémon's status section indicating it has Pokérus. This effect will now remain between 24 to 96 hours (1 to 4 days), depending on the Pokérus' strain and then disappear. During that time frame, the sick Pokémon can spread its infection to adjacent Pokémon inside your party. Once the time has passed, the Pokérus will disappear, making your Pokémon immune to the disease in the future. However, your Pokémon will still earn double Effort Values after its recuperation.
Note that storing an infected Pokémon inside a PC will let it keep the Pokérus indefinitely. This trick makes it easy to save Pokérus' benefits for later use by sporadically spreading the virus to other Pokémon in one's party by withdrawing said sick Pokémon. Most peculiar, from Generation 3 onwards, even Pokémon Eggs may catch Pokérus.
Generation specific EV information
Most of Generation 8's EV system remained unchanged, moving forward from Generation 3, 4, 5, 6, and 7.
In Pokémon Sword and Shield, Effort Values can be increased hourly by 4 points by attending Hammerlocke University seminars. These so-called Poké Jobs are always accessible once unlocked and are repeatedly usable to increase a Pokémon's Effort Values.
Pressing the X-button on a Pokémon's summary screen in Pokémon Sword and Shield will most likely display an orange-colored graph of its Effort Values – similar to the Generation 7 games. However, if this graph is cyan-colored, then your Pokémon has reached its maximum of 510 EVs. Single stats that have reached 252 Effort Values will sparkle.
Most of Generation 7's EV system remained unchanged, moving forward from Generation 3, 4, 5, and 6. However, the Macho Brace item and the Super Training introduced in Gen 3 and 6 were unavailable. In their stead, several old items got updated, and a new passive training form called "Poké Pelago" was introduced and acted as a resort of some sorts in which your Pokémon could grow on their own.
In the case of the updated items, these are the so-called Power items first introduced in Gen 4. They now yield eight Effort Values per defeated Pokémon, instead of four.
The newly introduced "Poké Pelago" is a collection of uninhabited islands reserved for the pleasure of Pokémon. Furthermore, this archipelago allows the passive EV-training of Pokémon currently stored in the PC depending on its level and is called Isle Evelup. The player can develop Isle Evelup through upgrades throughout the game, making it more effective training-wise. In detail, Pokémon can be assembled in groups up to 6 members each, to play and train with one another. All of these play/training sessions last for about 30 minutes, with a maximum of 99 sittings queueable. Pokémon occupied in play sessions cannot be accessed through the PC, but the player can end these play sessions prematurely while keeping their EV-training progress. Judging from the table down below, it would take 63 play sessions at level 3 to fully develop and max out a single stat of a Pokémon, as the maximum EVs in a stat cap out at 252 EVs. This undertaking would take up to 31 hours and 30 minutes but is halvable by placing Poké Beans in a designated crate on the island.
|Isle Evelup's level||EVs earned per session|
Another unusual EV training method is the so-called SOS Battle. An SOS Battle initiates when a wild Pokémon calls out for help, making an allied wild Pokémon join the battle. All wild Pokémon summoned this way get their EV yield doubled, making them extremely lucrative for EV-training.
Pressing the Y-button on a Pokémon's summary screen in Pokémon Sun, Moon, Ultra Sun, and Ultra Moon will most likely display an orange-colored graph of its Effort Values. However, if this graph is cyan-colored, then your Pokémon has reached its maximum amount of 510 EVs. Single stats that have reached 252 Effort Values will sparkle.
Most of Generation 6's EV system remained unchanged, moving forward from Generation 3, 4, and 5. However, a marginal change to streamline internal computation has been introduced, making individual stats max out at 252 EVs rather than at 255.
Generation 6 also introduced a new feature called the "Super Training," allowing players to increase Effort Values for each stat individually. Moreover, the "Super Training" menu now displayed not only a stat radar but also numerical values for every EV a Pokémon had. Additionally, the player could remove all Effort Values from a Pokémon entirely, creating a clean slate to train.
Another noteworthy addition was to reward a Pokémon Effort Values for catching wild Pokémon. Before Generation 6, Effort Values got only awarded for defeating Pokémon in battle.
In Pokémon X, Y, Omega Ruby, and Alpha Sapphire, the so-called Secret Super-Training Regiments became available to "Fully Trained Pokémon." These unique training sessions increase a Pokémon's EVs passively or by actively tapping punching bags once the EVs of a Pokémon has been reset (a Pokémon does not lose its "Fully Trained Pokémon" status once their EVs got reset).
Owning at least three "Fully Trained Pokémon" in Pokémon Omega Ruby and Alpha Sapphire will unlock a new area. This area is called the "Pathless Plain" and, depending on the day of the week, makes either Cobalion, Terrakion, or Virizion encounterable.
In Pokémon X, Y, Omega Ruby, and Alpha Sapphire, Super Training can be used to determine the Effort Values of a Pokémon. If a Pokémon reaches 510 Effort Values, it gets flagged as a "Fully Trained Pokémon."
Most of Generation 5's EV system remained unchanged, moving forward from Generation 3 and 4.
Noteworthy changes have been:
- EV-reducing Berries no longer reduced Effort Values down to 100 points when above that threshold. Instead, they now deduct 10 EVs on use.
- Pokémon now continued to gain Effort Values from battles at the maximum level (Level 100). Additionally, a Pokémon's stats got recalculated after every battle instead of after leveling up.
- A new set of EV-enhancing Wing items got introduced to the games. A list of these stat-enhancing items resides down below.
In Pokémon Black and White, an NPC living in Opelucid City will tell the player if the first Pokémon of their party has attained 510 Effort Values.
However, this has changed in Black 2 and White 2. Calling Bianca via the Xtransceiver in those two games, after the player has defeated the region's Champion, will make her tell the player whether a certain Pokémon in his or her party has attained 510 Effort Values in total. She also notifies the player if a Pokémon has reached 252 Effort Values in any given stat during that phone call.
Most of Generation 4's EV system remained unchanged, moving forward from Generation 3. However, EV-reducing Berries now reduced Effort Values above 100 points down to 100, disregarding how high the Effort Value count was before. Additionally, a new set of EV-enhancing Power items got introduced to the games. A list of these stat-enhancing items resides down below.
From Generation 4 onwards, a radar chart was incorporated into a Pokémon's summary screen indicating a Pokémon's Effort Values without giving specific numbers.
Generation 3 saw a complete overhaul of the Effort Value system. Pokémon were now limited to 255 Effort Values per stat, and 510 Effort Values in total. Meaning, you could theoretically max out two of a Pokémon's six stats or spread them out evenly.
Additionally, Generation 3 and 4 games recalculated a Pokémon's stats on level up. The same recalculation was triggered once a Vitamin or EV-reducing Berry got used on a Pokémon.
Before Generation 4, there was no way of directly viewing a Pokémon's Effort Values. You must keep track of your Pokémon's progress by other means, often resulting in keeping track with pen and paper.
Generation 1 and 2
In Generation 1 and 2, Effort Values got handled entirely differently than in subsequent games. In it, Effort Values were given out equally to a defeated Pokémon's species base stats.
Moreover, training for a specific set of EVs was unnecessary as every Pokémon could earn up to 65.536 EVs in every single stat (meaning 65.536 EVs in HP, Attack, Defense, Special, and Speed) as EV limitations got only implemented with the release of the third Generation. Usually, once a Pokémon reaches level 100, all possible EVs would have been acquired through battling trainers and wild Pokémon.
Note, that the number of stat points resulting from the earned EVs was the square root of the EVs divided by 4. This calculation reveals that the total number of extra stat points obtainable was about the same as it is now: 63.
Supporting items for EV-training
Over the Generations, Pokémon saw the introduction of many items supporting Pokémon trainers on their quest to train the best Pokémon in existence. These items are usually a great way to lessen the burden of long grinding sessions to raise specific EVs. Still, they often come at a price, being locked behind a large sum of Pokédollars or needing to be purchased through Battle Points earned in the region's Battle Facility.
Vitamins are a good starting point when you decide to EV-train your Pokémon as each of them adds 10 Effort Values to a specific stat on use. However, before Generation 8, their usage was limited as they could not raise any stat above the first 100 EVs earned in any given stat. Additionally, they can never increase the Effort Value count above 252 or 255 (depending on the game's Generation you are playing) for individual stats or 510 in total. There are 6 Vitamins in total, one for each stat:
|HP Up||HP||+10 Hit Point EVs|
|Protein||Attack||+10 Attack EVs|
|Iron||Defense||+10 Defense EVs|
|Calcium||Special Attack||+10 Special Attack EVs|
|Zinc||Special Defense||+10 Special Defense EVs|
|Carbos||Speed||+10 Speed EVs|
The Macho Brace
Introduced in Generation 3, the Macho Brace doubles the Effort Values gained in battle but cuts the pokémon's Speed in half. This halving is only temporary as unequipping the Macho Brace will restore the cut Speed stat fully.
|Macho Brace||Any||Cuts the Speed stat in half, but doubles the amount of EVs earned.|
Besides the Macho Brace, Generation 3 (Pokémon Emerald to be specific) saw the repurposing of particular Berries previously used to create Pokéblocks. These Berries now decrease specific Effort Values by 10 points, while increasing the Happiness (or Friendship) stat of the Pokémon that ate one of them. This stat reduction can be beneficial in reverting past mistakes during EV-training. There are six EV-decreasing Berries in total, one for each stat:
|Pomeg Berry||HP||-10 Hit Point EVs|
|Kelpsy Berry||Attack||-10 Attack EVs|
|Qualot Berry||Defense||-10 Defense EVs|
|Hondew Berry||Special Attack||-10 Special Attack EVs|
|Grepa Berry||Special Defense||-10 Special Defense EVs|
|Tamato Berry||Speed||-10 Speed EVs|
Introduced in Generation 4, Power items will increase your Effort Value yield tremendously by rewarding an additional 8 Effort Values depending on the Power item held. However, the trade-off for receiving increased Effort Values is a halved Speed stat. This halving is only temporary as unequipping the Power item will restore the cut Speed stat fully. There are six Power items in total, one for each stat:
|Power Weight||HP||Cuts the Speed stat in half, but awards +8 HP EVs after each battle.|
|Power Bracer||Attack||Cuts the Speed stat in half, but awards +8 Attack EVs after each battle.|
|Power Belt||Defense||Cuts the Speed stat in half, but awards +8 Defense EVs after each battle.|
|Power Lens||Special Attack||Cuts the Speed stat in half, but awards +8 Special Attack EVs after each battle.|
|Power Band||Special Defense||Cuts the Speed stat in half, but awards +8 Special Defense EVs after each battle.|
|Power Anklet||Speed||Cuts the Speed stat in half, but awards +8 Speed EVs after each battle.|
Introduced in Generation 5, Wings are similar in effect to Vitamins, but only increase the Effort Value count by one stat point on consumption. However, unlike Vitamins Wings are not limited to the first 100 EVs earned but can be used up until hitting the individual stat's maximum of 252 or 255 (depending on the game's Generation you are playing). There are 7 Wings in total, but only the following six contribute to your Pokémon's stat growth:
|Health Wing||HP||+1 Hit Point EV|
|Muscle Wing||Attack||+1 Attack EV|
|Resist Wing||Defense||+1 Defense EV|
|Genius Wing||Special Attack||+1 Special Attack EV|
|Clever Wing||Special Defense||+1 Special Defense EV|
|Swift Wing||Speed||+1 Speed EV|