Calculator Form
Catch Probability Chart
Example Data Table
| Pokemon | Max HP | Current HP | Catch Rate | Ball | Status | Approx Result |
|---|---|---|---|---|---|---|
| Rayquaza | 200 | 1 | 45 | Ultra Ball | Sleep | High legendary attempt |
| Groudon | 210 | 20 | 5 | Ultra Ball | Sleep | Very hard catch |
| Zigzagoon | 40 | 10 | 255 | Poke Ball | None | Very easy catch |
Formula Used
The Gen 3 modified catch value is:
X = (((3M - 2H) × C × B) / (3M)) × S
M is maximum HP. H is current HP. C is base catch rate. B is ball bonus. S is status bonus.
If X is 255 or more, the catch is treated as guaranteed. Otherwise, a shake value is calculated:
Y = 1048560 / fourthRoot(16711680 / X)
The single ball chance is estimated by:
Chance = (Y / 65536)^4
The chance after many balls is:
Total Chance = 1 - (1 - Single Chance)^Number of Balls
How to Use This Calculator
Enter the target name for your record. Add the target maximum HP and current HP. Use the in-game catch rate for that species. Choose the ball bonus that matches your item. Select the status condition. Then enter how many balls you plan to throw. Press calculate. The result appears above the form. Use CSV for spreadsheet records. Use PDF for quick sharing.
Article: Understanding Gen 3 Catch Rate
Why Catch Rate Matters
Gen 3 catching uses a compact formula. It turns health, ball strength, species rate, and status into one modified value. This value is not only a simple percent. The game also checks several shake tests. A stronger value gives better odds for each shake.
Health Is Very Important
Lower HP improves the chance greatly. A target at one HP is usually much easier to catch than one at half HP. This is why False Swipe is useful. It lets you reduce health safely. You get better odds without knocking the target out.
Status Adds Power
Status conditions improve the calculation. Sleep and freeze are the strongest common options. Paralysis, burn, and poison also help. Sleep is usually safer than poison or burn. Those conditions can damage the target over time. Paralysis is stable and useful for long battles.
Ball Choice Changes Strategy
Different balls use different multipliers. Ultra Ball is a common strong choice. Timer Ball can become powerful in longer battles. Net Ball helps against certain types. The calculator lets you test these cases before spending items.
Reading the Result
The per ball chance shows one throw. The multi-ball chance shows the chance across repeated throws. A low single chance can become acceptable after many attempts. The expected balls value estimates the average number of throws needed.
Practical Planning
Use the chart to see how extra balls affect success. If the curve rises slowly, improve the setup. Lower HP further. Add sleep or paralysis. Use a better ball. Small changes can produce large gains.
FAQs
What is a Gen 3 catch rate?
It is the capture system used in Ruby, Sapphire, Emerald, FireRed, and LeafGreen.
Does lower HP improve the result?
Yes. Lower current HP increases the modified catch value and improves success odds.
Which status is best?
Sleep and freeze usually give the strongest status bonus in this calculator.
Is one HP always required?
No. One HP is best, but many easy targets can be caught above one HP.
Why use multiple ball probability?
It shows the chance after repeated throws, not only one attempt.
Can the result be guaranteed?
Yes. If the modified value reaches 255 or more, the catch is treated as guaranteed.
Why does the graph curve flatten?
Each extra ball helps, but the remaining failure chance gets smaller each time.
Can I export my result?
Yes. Use the CSV button for data or the PDF button for a report.