Level

The level (Japanese: レベル level) is a measurement of how strong a Pokémon currently is. It is portrayed differently in the anime, games, manga, and Pokémon Trading Card Game.

In the core series
In the Pokémon games, a Pokémon's level is determined by how much experience it has. A Pokémon's level will range from 1 to 100. When a Pokémon gains a level, its stats increase by a small amount. Depending on the exact level, it may also learn a new move or evolve. A Pokémon's level is usually used to determine damage when the Pokémon uses an attacking move. Opponent's levels may be viewed in-battle, and players may see their own Pokémon's levels in-battle, in the PC or by using the menu.

Using a Rare Candy will increase a Pokémon's level by 1 (and increase its experience accordingly).

When a Pokémon levels up, it becomes more friendly. This way, Pokémon that evolve by friendship may eventually evolve by training.

In Generation IV, during battle, if a Pokémon almost has enough experience to level up, its Poké Ball will shake in the player's team summary.

In Generation I, if a Pokémon gains enough experience to gain more than one level, it will grow straight to the new level, and is unable to learn any move learned at a skipped level. In Generation II, the active Pokémon grows level by level, whereas switched out Pokémon grow straight to the new level (but are able to learn any moves regardless). From Generation III onwards, all Pokémon grow level by level.

Level cap
In the Pokémon games, the level cap is level 100. When a Pokémon has reached level 100, it cannot gain any more experience or level up. Due to this, previous to Generation VIII, level 100 Pokémon cannot evolve in any way which requires leveling up. From Generation VIII onwards, using a Rare Candy on a level 100 Pokémon is able to trigger these types of evolutions.

In Generations III and IV only, when a Pokémon has reached level 100, even if it has not gained maximum EVs, it cannot continue gaining EVs through battle (except Deoxys). Vitamins can still be used to raise EVs. In Generations I and II as well as from Generation V onwards, EVs can be gained even by level 100 Pokémon (although the Box trick is required in Generations I and II for the stats to update).

By exploiting the old man glitch in Generation I, a Pokémon can be acquired at a level higher than 100. Also in Generation I, any Pokémon can also be raised to a level above 100 via the Pokémon merge glitch; however, Pokémon in the Slow experience group need to be merged with a glitch Pokémon who requires even more experience at level 100. These Pokémon can continue to be leveled up with Rare Candies until level 255. Whenever a Pokémon over level 100 gains any experience, its level will revert to 100. If a Rare Candy is used on a level 255 Pokémon, it will revert to level 0 due to an overflow.

In Generations I and II, Pokémon were not legitimately available at a level below 2. This could be related to the fact that in Generations I and II, Pokémon in the Medium Slow experience group had a negative experience value at level 1, causing them to level up instantly to level 100 if they were to gain less than 54 experience points in battle (a high possibility on the games' early routes). Instead, Pokémon on the games' earliest routes were found level 2 or level 3, and starter Pokémon are given out at level 5. Likewise, Pokémon hatch from Pokémon Eggs at level 5.

From Generation III onwards, experience required to level up is taken from a lookup table, rather than by using a programmed equation as in Generations I and II; in Generation III, however, Pokémon still hatch from Eggs at level 5, and no wild Pokémon can be found at a level below 2. From Generation IV onwards, Pokémon hatch from Eggs at level 1 and some Pokémon are available in the wild at level 1 (however, starter Pokémon are still received at level 5).

Underleveled Pokémon
Through some unique circumstances, it is possible to have Pokémon at a lower level than they are usually available via evolution. Underleveled Pokémon appeared as early as Red and Green, with level 4-6 Kakuna and Metapod available in Viridian Forest. Kakuna and Metapod cannot be obtained by evolution until level 7.

Prior to Generation V, Pokémon obtained in in-game trades are always the same level as the one being traded away, so many underleveled Pokémon can be obtained through in-game trades. For example, in Red and Blue and FireRed and LeafGreen, it is possible to obtain an Electrode as low as level 3, even though the species evolves from Voltorb only at level 30 or above. This Electrode can be obtained by catching a Pikachu in Viridian Forest at level 3, evolving it with the Thunderstone, and trading it on Cinnabar Island.

Some non-player character Trainers use underleveled Pokémon in battle. For example, Lance has three underleveled Dragonite in Generations II and IV, with one being at level 50 and two at level 49 in HeartGold and SoulSilver (Dragonite does not evolve naturally from Dragonair until level 55). Many other in-game Trainers, such as Mars and Jupiter, also possess underleveled Pokémon.

An application of the Pomeg glitch in Emerald makes it possible to evolve a Pokémon while it is still inside an Egg, allowing any such evolved forms to be obtained at level 5. In Generation IV, this particular exploit of the Pomeg glitch was fixed; the Pomeg glitch was removed entirely in Generation V.

Disobedience

 * Main article: Obedience

Outsider Pokémon (Pokémon obtained via trade or event distribution) occasionally disobey the player's commands if they are above a certain level. The Badges the player owns determine the maximum level outsider Pokémon can be before there is a possibility for them to disobey. Not owning the region's second Badge means that no traded Pokémon whose level is above 10 (level 20 since Generation V) will obey the player; if the player has the region's eighth Badge, Pokémon will always obey.