Calculator
Formula used
The modified catch value is:
X = floor(((((3 × Max HP) - (2 × Current HP)) × (Rate × Ball Bonus)) / (3 × Max HP)) × Status Bonus)
If X is less than 1, it becomes 1. If X is 255 or more, the catch is guaranteed. Otherwise, the shake value is:
Y = floor(1048560 / floor(sqrt(floor(sqrt(floor(16711680 / X))))))
The chance per throw is:
Chance = (Y / 65536)^4
Apricorn balls from HeartGold and SoulSilver change the rate directly, then use a ball bonus of 1.
How to use this calculator
- Enter the target name, species catch rate, maximum HP, and current HP.
- Select the current status condition.
- Choose the ball and fill the fields that affect that ball.
- Set Safari stage only for Great Marsh or Johto Safari cases.
- Press the calculate button and read the result above the form.
- Use the CSV or PDF button to save the result.
Example data table
| Target | Rate | HP | Status | Ball | Condition |
|---|---|---|---|---|---|
| Giratina | 3 | 1 / 150 | Sleep | Dusk Ball | Night or cave |
| Beldum | 3 | 10 / 100 | Paralysis | Ultra Ball | No special condition |
| Snorlax | 25 | 20 / 260 | Sleep | Heavy Ball | Weight bonus applies |
| Lapras | 45 | 8 / 180 | Freeze | Net Ball | Water type |
Gen Four Capture Physics Guide
Why the model matters
A Gen Four catch rate calculator helps players judge one throw before wasting rare balls. The method looks simple, yet several hidden factors change the final chance. Hit points matter first. A weak target has a larger modified catch value. Status also matters. Sleep and freeze double the value. Paralysis, poison, and burn add a smaller bonus.
Ball pressure and conditions
The ball choice is the next major force. A plain ball keeps the species rate unchanged. Great and Ultra balls raise the ball bonus. Dusk, Net, Dive, Repeat, Quick, Timer, and Nest balls depend on battle context. This tool asks for those context switches, then applies the proper multiplier. HeartGold and SoulSilver Apricorn balls need special care. They change the species catch rate directly, not the normal ball bonus. Heavy Ball is different again, because it adds or subtracts points by weight.
Shake checks
The calculator also shows the shake value. Generation Four does four shake checks. Each check compares a random number with the calculated shake value. All four checks must pass. That is why the displayed chance can differ from the rough modified value divided by 255. Rounding can push some values into surprising bands.
Planning throws
Use the advanced fields when planning legendary hunts. Enter the real max HP and current HP after damage. Add the species catch rate from a trusted database. Pick the exact ball and set each condition truthfully. Then review the chance per throw, expected balls, and cumulative odds. The results are not a promise. They are the same probability model used to guide the game calculation.
Learning from results
This page is useful for routing, challenge runs, shiny hunts, and classroom probability examples. It connects game capture rules with basic physics language. Lower HP acts like stronger pressure on the final outcome. Better balls act like improved efficiency. More throws create a geometric chance curve. Export the table when you want notes for later attempts. The CSV file helps with spreadsheets. The PDF file is easy to save with a hunt plan.
Because the inputs are open, you can test unusual cases too. Try full health, one HP, different status choices, and late Timer Ball throws. The comparison makes risk clear. It also teaches how independent shake checks build final probability well.
FAQs
Does this calculator cover all Gen Four games?
It covers Diamond, Pearl, Platinum, HeartGold, and SoulSilver style capture math. It also includes HGSS Apricorn ball options.
Is a Master Ball always successful?
Yes. Master Ball and Park Ball bypass the normal shake formula. The result is treated as guaranteed.
Why do Apricorn balls work differently?
In HeartGold and SoulSilver, Apricorn balls change the species catch rate directly. Then they use a normal ball bonus of 1.
What does current HP do?
Lower current HP raises the modified catch value. One HP gives the strongest normal HP advantage without fainting the target.
Which status is best?
Sleep and freeze are strongest in this generation. Paralysis, poison, and burn help, but their bonus is smaller.
How does Timer Ball use turns?
Enter turns passed before the throw. The bonus starts at 1 and rises until it reaches the maximum value of 4.
Why is the rough chance different from X divided by 255?
The game converts X into a shake value. Four independent shake checks and integer rounding can change the final chance.
Can I export the result?
Yes. Submit the form first. Then use the CSV or PDF button in the result section.