How Is Damage Calculated in Pokémon RBY?

Damage in Pokémon Red and Blue (RBY) is calculated using a formula based on the attacking Pokémon’s level, move power, Attack or Special stat, the defender’s corresponding Defense or Special stat, and battle modifiers. Type effectiveness, Same-Type Attack Bonus (STAB), critical hits, and a random damage factor can change the final amount of HP lost.

Pokémon RBY refers to the original Generation I games, Pokémon Red, Blue, and Yellow are often discussed together, although this guide focuses on the original Red and Blue battle mechanics. Understanding the damage formula helps players predict knockouts, compare moves, and make better competitive battling decisions.