Methods of evolution

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There are numerous Methods of Evolution, which determine when Pokémon evolve and, in some cases, what they evolve into. Most Pokémon, about one third, will evolve by leveling up while others evolve through specific means, such as being traded, achieving maximum happiness, using an evolution stone.

Triggers

In Generation I Pokémon evolved though only three methods.

Several variation have been added in subsequent Generations.

Pokémon from branched evolution families may evolve into different forms depending on the evolution trigger and/or other conditions.

Evolution by Level

Most Pokémon are able to evolve by leveling up up. This can be triggered by gaining experience in battle or using a Rare Candy. Some Pokémon may also require additional conditions before evolution will take place, such as a specific move being known. It should be noted that a Pokémon left in Daycare will not evolve, even if all conditions are met, until it's leveled up (or given a Rare Candy) while in the party.

Reaching a Certain Level

Amongst the Pokémon that evolve by level, the majority of Pokémon will evolve as soon as certain level is reached. If a Pokémon is not able to evolve when it reaches the required level, it will try to evolve again every time it levels up. To avoid this, an Everstone can be given to the Pokémon, which will suppress evolution until it is removed.

Example:

Lowest	Trigger	Highest
Rattata	Level 20	Raticate

This method of evolution usually doesn't have any special disadvantages. However, Meowth, for example, evolves into Persian at level 28, but learns Pay Day at level 32. In Generation IV Persian cannot learn Pay Day by leveling up, this means that if a player wants to have a Persian with Pay Day, the player must not let Meowth evolve until it learns the move.

Furthermore, Pokémon that evolve by level can no longer evolve if they are still in their base form at level 100, as they cannot level up any further.

Happiness

Some Pokémon evolve by leveling up when their hidden Happiness stat is 220 or above. It's more common with baby Pokémon such as Cleffa, but other evolved Pokémon like Chansey (which evolves further into Blissey) require it. This method of evolution was introduced in Generation II.

The following Pokémon evolve in this manner:

Generation II:	Generation III:	Generation IV:
Pichu → Pikachu Cleffa → Clefairy Igglybuff → Jigglypuff Golbat → Crobat Chansey → Blissey Togepi → Togetic	Azurill → Marill	Munchlax → Snorlax Buneary → Lopunny

By Happiness and Time

The following Pokémon evolve by leveling up if they're happy, but only during a certain part of the day:

Day:

Night:

Eevee → Umbreon
Chingling → Chimecho

Evolving by Item

By Evolutionary Stone

Main article: Evolutionary stone

See also: Pokémon that evolve by evolutionary stone

Many Pokémon evolve when they are exposed to an evolutionary stone. The stone may be applied at any time and causes an instant evolution. The player can decide whether and when to evolve his or her Pokémon, but must choose carefully as most Pokémon will no longer be able to learn certain moves when they evolve in this way, and some (like Raichu and Togekiss) cannot learn any moves by leveling up, although there are exceptions to this rule. However, certain moves are exclusive to the stone-evolved Pokémon.

Examples:

Before	Stone	After	Before	Stone	After
Shellder	Water Stone	Cloyster	Eevee	Water Stone	Vaporeon
Pikachu	Thunder Stone	Raichu	Eevee	Thunder Stone	Jolteon
Vulpix	Fire Stone	Ninetales	Eevee	Fire Stone	Flareon
Weepinbell	Grass Stone	Victreebel	Nuzleaf	Grass Stone	Shiftry
Clefairy	Moon Stone	Clefable	Skitty	Moon Stone	Delcatty
Gloom	Sun Stone	Bellossom	Sunkern	Sun Stone	Sunflora
Togetic	Shiny Stone	Togekiss	Roselia	Shiny Stone	Roserade
Murkrow	Dusk Stone	Honchkrow	Misdreavus	Dusk Stone	Mismagius

While there are usually no additional requirements for stone-induced evolution, there are some exceptions. As of Generation IV there are only two such exceptions, with the two Pokémon who can evolve via Dawn Stone having a gender requirement.

Before	Stone	After
Kirlia ♂	Dawn Stone	Gallade
Snorunt ♀	Dawn Stone	Froslass

Note that sometimes the Oval Stone is said to be an evolutionary stone, because it is a stone and it is required for an evolution. However, an Oval Stone is technically an evolution-inducing held item.

Holding a Certain Item and Time

Some Pokémon will evolve when they level up while holding a certain item, during a certain time of day. In this case, the item disappears after the Pokémon evolves. As of Generation IV, there are no held item evolutions that do not have a time requirement

Before	Hold Item + Time	After
Happiny	Oval Stone During the Day	Chansey
Gligar	Razor Fang At Night	Gliscor
Sneasel	Razor Claw At Night	Weavile

Evolution via Trading

Main article: Trade

A select few Pokémon evolve only when they are traded. The evolution starts immediately after the trade is completed, regardless of the method of trading used.

Before	After
Kadabra	Alakazam
Machoke	Machamp
Graveler	Golem
Haunter	Gengar

A well-known mistranslation in the non-Japanese releases of the Generation I games suggested, that after trading a man a Raichu, it evolved. This fueled speculation as to whether or not there would be a third stage to the Pikachu line in Generation II. A third stage was later realized, but in the form of a baby Pokémon, Pichu.

Holding a Certain Item During a Trade

Main article: Evolution-inducing held item

See also: Pokémon that evolve by trading with a held item

Some Pokémon evolve when traded only if they are holding a certain item. Like any evolution-inducing held item, the item disappears after the Pokémon evolves.

The following Pokémon evolve using this method:

Before	Item	After	Before	Item	After
Poliwhirl	King's Rock	Politoed	Slowbro	King's Rock	Slowking
Onix	Metal Coat	Steelix	Scyther	Metal Coat	Scizor
Rhydon	Protector	Rhyperior	Seadra	Dragon Scale	Kingdra
Electabuzz	Electirizer	Electivire	Magmar	Magmarizer	Magmortar
Porygon	Up-Grade	Porygon2	Dubious Disc		Porygon-Z
Dusclops	Reaper Cloth	Dusknoir	Clamperl	DeepSeaTooth	Huntail
Dusclops	Reaper Cloth	Dusknoir	Clamperl	DeepSeaScale	Gorebyss

By Move

Some Pokémon evolve when level up while knowing a particular move. The moves are available by leveling up, however, if the Pokémon is not allowed to learn the move, or are made to forget the move before being allowed to evolve, the Pokémon must relearn it with the help of the Move Relearner. This method of evolution was introduced in Generation IV.

Rollout:

Before	After
Lickitung	Lickilicky

AncientPower:

Before	After
Tangela	Tangrowth
Yanma	Yanmega
Piloswine	Mamoswine

Double Hit:

Before	After
Aipom	Ambipom

Mimic:

Before	After
Mime Jr.	Mr. Mime
Bonsly	Sudowoodo

By Location

Beginning with the Generation IV games, some Pokémon only evolve by leveling up in the specific area.

Mt. Coronet:

Before	After
Magneton	Magnezone
Nosepass	Probopass

Eterna Forest (Moss Rock):

Before	After
Eevee	Leafeon

Route 217 (Ice Rock):

Before	After
Eevee	Glaceon

Other Methods

The following Pokémon evolve through a method that is isolated to their evolution line only.

Mantyke evolves into Mantine when it levels up only if there is a Remoraid in user's party.
When Nincada evolves into Ninjask (at level 20), if there is an empty slot in the party (and, in Generation IV, if the player has a spare Poké Ball in their bag) Shedinja will appear.
Feebas evolves into Milotic by leveling up when its Beauty stat is 170 or above.
Combee only evolves into a Vespiquen if it is female. Male Combee do not evolve.

Additional Factors

Some Pokémon from branched evolution families evolve into different forms depending on additional factors, not listed above. These factors are not conditions for evolution, since they do not determine the possibility of evolution, but what the Pokémon will become after evolution.

Burmy

This Pokémon evolves at level 20, but its new form is determined by its gender and/or cloak (the cloak changes based on the place where it last battled).
- Male Burmy → Mothim
- Female Burmy → Wormadam, but the type combination of Wormadam is determined by the cloak.
  - With Plant cloak (after battling in the wild) → Bug/Grass Wormadam
  - With Sandy cloak (after battling in a cave or on a beach) → Bug/Ground Wormadam.
  - With Trash cloak (after battling in a building) → Bug/Steel Wormadam.

Tyrogue

This Pokémon evolves at level 20. What it evolves into depends on its stats.
- If its Defense is higher than Attack, it evolves into Hitmonchan
- If its Attack is higher than Defense, it evolves into Hitmonlee.
- If Attack is equal to Defense, it evolves into Hitmontop.

Wurmple

Evolves at level 7 into either Silcoon or Cascoon, depending on its personality value. This value is hidden, determined when Pokémon is caught and cannot be affected by the player. See the article about Personality value for the exact formula.