Pokémon Gen 5 Catch Rate Calculator
Optimized for Black, White, Black 2, and White 2
Catch Probability
How the Gen 5 Catch Formula Works
In Generation 5 (Pokémon Black, White, Black 2, and White 2), the catch rate formula underwent specific adjustments to account for internal math changes and the introduction of the Critical Catch mechanic. This calculator uses the official math used by the DS hardware.
The Core Formula
The game first calculates a value 'a':
Calculation Parameters
- Max HP & Current HP: Reducing a Pokémon to 1 HP significantly increases 'a'.
- Base Catch Rate: A hidden value for every species. For example, Zekrom and Reshiram have a catch rate of 45 in BW, while most legendaries like Victini or Kyurem have a rate of 3.
- Status Multiplier: Sleep and Freeze are the most effective, providing a 2x bonus. Paralyze, Burn, and Poison provide a 1.5x bonus.
- Ball Bonus: Different balls have different multipliers based on conditions (e.g., Dusk Ball provides 3.5x at night).
Shake Checks
If 'a' is less than 255, the game calculates a shake probability 'b':
The Pokémon is caught if four random numbers generated by the game are all less than 'b'. This is why the ball shakes four times before a successful capture.
Examples for Gen 5
Example 1: Catching Kyurem
Kyurem has a base catch rate of 3. If it is at 1/100 HP, asleep, and you use a Dusk Ball at night:
- Max HP: 100, Current HP: 1
- Status: 2.0 (Sleep)
- Ball: 3.5 (Dusk Ball)
- Result: Approximately ~7.5% per ball.
Example 2: Catching a Level 5 Patrat
Patrat has a base catch rate of 255. Even at full health with a standard Poké Ball, you have a nearly 100% chance of success because 'a' will exceed 255 immediately.