Pokemon Black & White Catch Rate Calculator
(e.g., Zekrom/Reshiram: 45, Common: 255)
None (1x)
Sleep / Freeze (2.5x)
Paralysis / Burn / Poison (1.5x)
Poke Ball (1x)
Great Ball (1.5x)
Ultra Ball (2x)
Dusk Ball (Inside Cave or at Night) (3.5x)
Quick Ball (Turn 1) (5x)
Net Ball (Water/Bug Type) (3x)
Timer Ball (Turn 30+) (4x)
Master Ball (Auto-Catch)
Catch Probability:
0%
Mastering Pokemon Catching in Gen 5
In Pokemon Black, White, Black 2, and White 2, the mechanics for catching Pokemon received a significant update from previous generations. The formula considers the HP of the Pokemon, its base catch rate, the ball you are using, and any status conditions applied. This calculator specifically replicates the "Modified Catch Rate" logic used in Generation 5.
The Catch Rate Formula (Generation 5)
The core calculation for the modified catch rate (often called 'a') in Pokemon Black and White is:
a = (((3 * HP_max – 2 * HP_current) * BaseRate * BallModifier) / (3 * HP_max)) * StatusModifier
If the resulting value 'a' is 255 or higher, the Pokemon is caught automatically. Otherwise, the game calculates the probability of success. In Generation 5, the probability is approximately (a / 255).
Key Factors for Success
- Status Conditions: In Gen 5, Sleep and Freeze are significantly more effective than in previous games, providing a 2.5x multiplier to your catch rate. Paralysis, Burn, and Poison provide a 1.5x multiplier.
- Base Catch Rate: Every Pokemon species has a hidden number from 1 to 255. Common Pokemon like Patrat have a rate of 255, making them easy to catch. Legendary Pokemon like Reshiram and Zekrom have a rate of 45 (which is unusually high for box legendaries) to ensure players can catch them for the story's climax.
- HP Management: Reducing a Pokemon's HP is critical. Using the move False Swipe is the best strategy, as it leaves the target with exactly 1 HP, maximizing the modifier from the HP portion of the formula.
Calculation Examples
| Scenario | HP | Ball | Approx. Chance |
|---|---|---|---|
| Standard Catch (Full HP) | 100% | Poke Ball | Low |
| Legendary at 1 HP (Sleep) | 1 HP | Ultra Ball | ~35% – 45% |
| Quick Ball (Turn 1) | 100% | Quick Ball | High |