Catching Pokémon is a core mechanic in the Pokémon series, and behind the satisfying "Gotcha!" lies a complex formula that determines your chances of successfully capturing a wild Pokémon. This calculator helps you understand and predict those odds.
The Formula Explained
The base catch rate formula, as implemented in many core series games, involves several factors:
Base Catch Rate: Each Pokémon species has a base catch rate, a value from 0 to 255, indicating how inherently difficult it is to catch. Higher values mean easier captures.
Pokémon Level: The level of the wild Pokémon significantly impacts catch rate. Higher levels generally make them harder to catch.
Current HP: The lower a Pokémon's current HP is, the higher your catch rate becomes. Being close to fainting a Pokémon greatly increases your chances.
Status Effect: Inflicting status conditions like Sleep, Freeze, Poison, Burn, or Paralysis on the wild Pokémon substantially boosts the catch rate. Sleep and Freeze offer the largest bonuses.
Ball Modifier: Different Poké Balls have different effectiveness. Standard Poké Balls have a modifier of 1, Great Balls increase it to 1.5, and Ultra Balls to 2. Specialized balls like the Master Ball have a modifier of 255, guaranteeing a catch.
Critical Capture: A relatively newer mechanic, a critical capture (if it occurs) provides a significant boost to the catch rate, making a difficult catch much more manageable.
How the Calculator Works
Our calculator takes these variables and applies the following simplified, yet commonly accepted, formula to estimate the catch probability:
Catch Rate = (((3 * Max HP - 2 * Current HP) * Base Catch Rate * Ball Modifier) / (3 * Max HP)) * (Status Bonus) * (Critical Capture Bonus)
Where:
Status Bonus: 1.0 for no status, 2.0 for Sleep/Freeze, 1.5 for Poison/Burn/Paralysis.
Critical Capture Bonus: Varies, but often around 2.5x if enabled.
This calculated rate is then often used in conjunction with a random number generator and further calculations involving shake counts of the Poké Ball to determine the final outcome.
Example Scenario
Let's say you encounter a Level 50 Pikachu with a Base Catch Rate of 190. Your Pikachu is at 30/60 HP, you've inflicted Paralysis on it (Status Modifier: 1.5), and you're using an Ultra Ball (Ball Modifier: 2). You also get lucky and trigger a Critical Capture (Bonus: 2.5).
Using the calculator with these inputs:
Base Catch Rate: 190
Pokémon Level: 50 (Note: Level itself is often implicitly factored into the base catch rate or other game mechanics, and this simplified formula focuses on other direct modifiers for clarity.)
Current HP: 30
Max HP: 60
Status Effect: 2 (representing Paralysis, Poison, Burn)
Ball Type: 2 (Ultra Ball)
Is Critical: 1 (Yes)
The calculator will provide an estimated probability, helping you gauge your chances!
function calculateCatchRate() {
var baseCatchRate = parseFloat(document.getElementById("catchRate").value);
var pokemonLevel = parseFloat(document.getElementById("level").value); // Level is often used implicitly or in more complex versions
var hpCurrent = parseFloat(document.getElementById("hpCurrent").value);
var hpMax = parseFloat(document.getElementById("hpMax").value);
var status = parseInt(document.getElementById("status").value);
var ballModifier = parseFloat(document.getElementById("ballType").value);
var isCritical = parseInt(document.getElementById("isCritical").value);
var resultDiv = document.getElementById("result");
if (isNaN(baseCatchRate) || isNaN(pokemonLevel) || isNaN(hpCurrent) || isNaN(hpMax) || isNaN(status) || isNaN(ballModifier) || isNaN(isCritical)) {
resultDiv.innerHTML = "Please enter valid numbers for all fields.";
return;
}
if (hpMax <= 0) {
resultDiv.innerHTML = "Max HP must be greater than 0.";
return;
}
if (hpCurrent hpMax) {
resultDiv.innerHTML = "Current HP cannot be greater than Max HP.";
return;
}
if (status 2) {
resultDiv.innerHTML = "Status effect must be 0, 1, or 2.";
return;
}
if (isCritical 1) {
resultDiv.innerHTML = "Critical capture must be 0 or 1.";
return;
}
if (baseCatchRate 255) {
resultDiv.innerHTML = "Base Catch Rate must be between 0 and 255.";
return;
}
var hpFactor = (3 * hpMax – 2 * hpCurrent) / (3 * hpMax);
var statusBonus = 1;
if (status === 1) { // Sleep or Freeze
statusBonus = 2;
} else if (status === 2) { // Poison, Burn, Paralysis
statusBonus = 1.5;
}
var criticalBonus = 1;
if (isCritical === 1) {
// This is a simplification. Actual critical capture bonus can be complex.
// For Gen 6+, it's based on a value 'a' which is usually around 2.5
criticalBonus = 2.5;
}
// A simplified calculation, not accounting for specific game mechanics like shake counts directly
// This focuses on the "potential" catch rate based on inputs.
var catchModifier = hpFactor * statusBonus * ballModifier * criticalBonus;
// The final catch probability calculation can be quite complex and game-specific.
// This formula attempts to give a general idea of how much your modifiers affect the base rate.
// A common approach to express the final probability is `1 – (1 – (BaseRate * Modifier) / 255)^4` or similar.
// For simplicity, we'll calculate a raw "catch value" that can be interpreted.
// Using a common simplified formula structure that incorporates most factors
var modifiedCatchRate = ((3 * hpMax – 2 * hpCurrent) * baseCatchRate * ballModifier) / (3 * hpMax);
modifiedCatchRate = modifiedCatchRate * statusBonus;
if(isCritical === 1) {
// For Gen 6+, critical capture modifies this value directly.
// A common simplification is to multiply by a factor.
modifiedCatchRate = modifiedCatchRate * 2.5; // Simplified critical bonus
}
// The actual probability is often calculated as:
// P = 1 – (1 – (modifiedCatchRate / 255))^4 (for older gens)
// P = 1 – (1 – (modifiedCatchRate / 255))^X (where X varies)
// or for Gen 6+ critical capture:
// P = 1 – (1 – (a * b * c / 255))^4 where a, b, c are modifiers
// To provide a more direct "chance" value:
var finalCatchValue = modifiedCatchRate;
// Cap the effective value to what's possible within the formula structure
if (finalCatchValue > 255) {
finalCatchValue = 255;
}
if (finalCatchValue < 0) {
finalCatchValue = 0;
}
// Calculate a probability percentage based on a common formula structure (e.g., Gen 1-5 style with 4 shakes)
var probability = 1 – Math.pow(1 – (finalCatchValue / 255), 4);
// For Gen 6+ critical capture, the calculation is different. This calculator uses a blend for general understanding.
// If critical capture is enabled, it assumes a significantly higher chance.
// For simplicity, we'll present a percentage based on the modifiers.
var outputHTML = "