Happiness

Happiness is a number between 0 and 255 that gauges how friendly a Pokémon is towards its trainer.

Every Pokémon starts with a base happiness, which will change based on certain events:

• Keeping the Pokémon outside of its Poké Ball will cause it to slowly gain happiness.
• Leveling up the Pokémon will raise happiness.
• Letting the Pokémon faint will lower happiness.
• Using a Pomeg Berry, Kelpsy Berry, Qualot Berry, Hondew Berry, Grepa Berry, or Tamato Berry on a Pokémon will raise happiness.
• Using an HP Up, Protein, Iron, Calcium, Zinc, or Carbos on a Pokémon will raise happiness.
• Trading the Pokémon will reset its happiness to 70.
• Capturing a Pokémon in a Friend Ball will set its initial happiness to 200 rather than its base happiness.
• Capturing the Pokémon in a Luxury Ball or letting the Pokémon hold a Soothe Bell will cause events that raise happiness to increase happiness by an additional one point each. These two conditions can stack with each other.

Evolution

A happiness of 220 or more upon leveling up is necessary to evolve:

• Golbat→Crobat
• Eevee→Espeon (day)
• Eevee→Umbreon (night)
• Pichu→Pikachu
• Igglybuff→Jigglypuff
• Munchlax→Snorlax
• Riolu→Lucario (day)
• Swadloon→Leavanny
• Chansey→Blissey

Bugs

• Pokémon start at 0 happiness rather than their base happiness.