Understanding This Calculator
Since Generation III, Pokémon games determine catch success using a formula that weighs the target’s remaining HP, its species’ base catch rate, the ball used, and any status condition. Lowering a Pokémon’s HP and inflicting sleep or paralysis are the two biggest levers a trainer controls.
The formula produces an intermediate value called “a” — when a reaches or exceeds 255, or a Master Ball is used, the catch is guaranteed. Below that threshold, the game performs up to four probabilistic “shake checks,” and this calculator approximates the resulting overall catch probability.
- MaxHP target’s maximum HP
- CurHP target’s current HP
- Rate species’ base catch rate (1-255)
- Ball ball catch-rate multiplier
- Status status condition multiplier
This calculator implements the publicly documented Gen III+ catch-rate formula (widely published on community wikis); it performs only this factual math and does not reproduce any game text, art, or branding.
Frequently Asked Questions
Why does the Master Ball always succeed?
The Master Ball is coded to skip the catch-rate calculation entirely and always succeed, which is why it’s treated as a guaranteed catch in this calculator rather than plugged into the standard formula.
Does lowering HP matter more than status conditions?
Both matter, but they interact multiplicatively — reducing a target to 1 HP roughly triples the “a” value compared to full HP, while sleep or freeze doubles it on top of that, so combining low HP with a status condition gives the highest realistic catch chance short of a Master Ball.