Catching Pokémon is a fundamental mechanic in the Pokémon games, and understanding the underlying mechanics can significantly improve your success rate. The "catch rate" is a hidden value for each Pokémon species that determines how likely it is to be caught by a Poké Ball. Several factors influence this rate during a battle.
Factors Affecting Catch Rate:
Pokémon's Base Catch Rate: Each species has a unique base catch rate, ranging from 1 (legendary Pokémon) to 255 (common Pokémon like Magikarp). A higher base catch rate means the Pokémon is inherently easier to catch.
Pokémon's Current HP: The lower the Pokémon's current HP, the higher your chances of catching it. A severely weakened Pokémon is much more likely to be captured than a full-health one.
Status Conditions: Inflicting status conditions like Sleep or Paralysis significantly increases the catch rate. Burn, Poison, and Freeze also provide a boost, though generally less than Sleep or Paralysis.
Poké Ball Type: Different Poké Balls have different modifiers. Standard Poké Balls have a modifier of 1.0x. Great Balls offer a higher modifier (e.g., 1.5x), and Ultra Balls even higher (e.g., 2.0x). Special balls like the Master Ball have a 255x modifier, guaranteeing a catch.
Trainer Level vs. Pokémon Level (in some games): In certain generations or specific battle scenarios, a modifier might be applied if the trainer's Pokémon are a significantly different level than the wild Pokémon. For simplicity in this calculator, we use a general level modifier.
The Catch Rate Formula (Simplified):
The exact formula can be complex and varies slightly between game generations. However, a common simplified approach involves calculating a "catch coefficient" and then determining the probability. The core idea is that a higher HP percentage, absence of status, and weaker ball all decrease your chances, while the opposite increases them.
This calculator uses a simplified model that incorporates these key factors to give you an estimated catch probability.
How to Maximize Your Catch Chances:
Weaken the Pokémon: Use attacks that deal damage but don't knock the Pokémon out. Aim for low HP.
Inflict Status Conditions: Use moves like "Thunder Wave" for paralysis or "Sleep Powder" for sleep.
Use the Right Ball: Employ stronger Poké Balls like Great Balls or Ultra Balls for better odds. For legendary or difficult Pokémon, consider saving your Master Ball.
Using this calculator can help you strategize and determine the best approach for catching that elusive Pokémon!
function calculateCatchRate() {
var pokemonHP = parseFloat(document.getElementById("pokemonHP").value);
var maxHP = parseFloat(document.getElementById("maxHP").value);
var statusCondition = parseInt(document.getElementById("statusCondition").value);
var catchRate = parseFloat(document.getElementById("catchRate").value);
var ballModifier = parseFloat(document.getElementById("ballModifier").value);
var levelModifier = parseFloat(document.getElementById("levelModifier").value);
var resultDiv = document.getElementById("catchResult");
resultDiv.innerHTML = ""; // Clear previous results
// Input validation
if (isNaN(pokemonHP) || isNaN(maxHP) || isNaN(catchRate) || isNaN(ballModifier) || isNaN(levelModifier) || maxHP <= 0 || pokemonHP < 0 || catchRate 255 || ballModifier < 0 || levelModifier maxHP) {
pokemonHP = maxHP;
document.getElementById("pokemonHP").value = maxHP; // Update input field for clarity
}
// Calculate HP factor
var hpFactor = (maxHP * 3) – (pokemonHP * 2);
if (hpFactor < 0) hpFactor = 0; // Ensure it's not negative
// Calculate status factor
var statusFactor = 1;
if (statusCondition === 1) { // Sleep/Freeze
statusFactor = 2.5;
} else if (statusCondition === 2) { // Paralysis/Poison/Burn
statusFactor = 1.5;
}
// Calculate the modified catch rate
// This is a simplified formula, actual formulas vary by game generation.
// The core idea is (BaseRate * HP_Factor * Status_Factor * Ball_Modifier * Level_Modifier) / some_divisor
// We'll aim for a percentage probability.
// A common simplified way to represent catch probability:
// Calculate a value, then compare it against a random number.
// Let's estimate a catch "score"
var catchScore = (catchRate * hpFactor * statusFactor * ballModifier * levelModifier);
// We need a divisor that scales this score into a probability.
// This divisor is also complex and game-dependent.
// For a simplified estimation, we can cap the score and relate it to a common maximum value.
// Let's assume a max possible score that should generally lead to a high catch rate.
// A common threshold for a good catch chance might be around 255 * 3 * 2.5 * 2.0 * (some level relation)
// Let's aim for a simpler percentage representation based on the raw factors.
// A very basic representation of probability (not strictly accurate to all games but illustrative):
// Let's say the max possible value of the numerator components (ignoring level modifier for a moment, and assuming max HP, no status, best ball)
// is roughly proportional to the difficulty.
// Another way is to compute a final "a" value and compare it to a random number from 0 to 255.
// Let's try to output a probability percentage for simplicity.
// A common simplified formula component:
var numerator = Math.floor(hpFactor * statusFactor * catchScore); // Use catchScore for the base rate part
// The actual divisor is highly game-specific. Let's approximate it.
// In Gen 1, for example, it involved (MaxHP * 255 * 4) in the denominator for a ball with modifier 1.
// For a generalized percentage output, we can try to normalize this.
// Let's try a different approach: calculate the "catch coefficient" (a value usually between 0 and 255)
// and then estimate the probability.
// Simplified Catch Coefficient Calculation (similar to some later gens)
var catchCoefficient = Math.floor(((maxHP * 3) – (pokemonHP * 2)) * statusFactor * ballModifier * levelModifier);
catchCoefficient = Math.max(0, catchCoefficient); // Ensure non-negative
// The actual final check involves a random number and often another multiplier based on the ball type and maybe level.
// Let's aim for a probability percentage. A common denominator for catch calculation is often related to 65535 or 255.
// Simplified probability estimation:
// Let's consider a "target value" for a catch.
// Assume the calculated catchScore (which includes base catch rate) is a primary driver.
// Higher score means higher chance.
// Let's use a divisor that creates a scale, say, out of 1000, and then convert to percentage.
// The exact numbers for division are highly game-dependent.
// Let's use a heuristic divisor. A value around 255 * 3 * 2.5 * 2.0 * 2 (for level) is quite high.
// Let's derive a probability based on the components.
var finalCatchProbability = (catchRate / 255.0) * (hpFactor / (maxHP * 3.0)) * statusFactor * ballModifier * levelModifier;
// This is still a very rough estimation. Let's try to follow a more established simplified formula structure.
// Let's use a common formula structure that results in a probability:
// Formula sketch: P = 1 – exp(-K * A) where K is a constant and A is the adjusted catch rate.
// Or a simpler form: P = (Adjusted Catch Rate) / (Max Possible Adjusted Catch Rate)
// Let's try calculating an adjusted catch value 'A' based on factors.
// Assume 'a' is the base catch rate (0-255).
// Max HP = H, Current HP = h
// Status Modifier = s (0=None, 1=Sleep/Freeze, 2=Paralyze/Poison/Burn)
// Ball Modifier = b
// Level Modifier = l
// A common structure for the adjusted catch value (let's call it 'a_prime'):
// a_prime = a * (3*H – 2*h) / (3*H) * s * b * l
// This needs to be normalized. The actual check is usually:
// random_number 1.
// The formula needs to result in a value <= 1 to represent probability.
// Let's ensure the multipliers are within a reasonable range or divide by a scaling factor.
// Let's try a common simplified approach that yields a value between 0 and 1.
// Factors: Base Catch Rate (0-255), HP (Current/Max), Status, Ball, Level.
// A common calculation involves getting a value and comparing it to a random number.
// Let's aim for a percentage displayed.
// Simplified Catch Algorithm:
// 1. Calculate Attack Factor: (MaxHP * 3 – CurrentHP * 2)
// 2. Apply Status Modifier
// 3. Apply Ball Modifier
// 4. Apply Level Modifier
// 5. Combine with Base Catch Rate.
// Let's use a common formula structure found in many fan wikis:
// Adjusted_Catch_Rate = (Base_Catch_Rate * (Max_HP * 3 – Current_HP * 2) * Status_Modifier * Ball_Modifier * Level_Modifier) / Divisor
// The Divisor is complex. Let's try to output a percentage directly.
// Let's try calculating a "catch score" and then estimating probability from it.
// Score = BaseCatchRate * HP_Multiplier * Status_Multiplier * Ball_Multiplier * Level_Multiplier
// HP_Multiplier = (MaxHP * 3 – CurrentHP * 2) / (MaxHP * 3) (this is often used)
// Let's use this more standard HP multiplier.
var hpMultiplierStandard = ((maxHP * 3) – (pokemonHP * 2)) / (maxHP * 3);
hpMultiplierStandard = Math.max(0, hpMultiplierStandard); // Ensure it's not negative
var finalCatchValue = catchRate * hpMultiplierStandard * statusFactor * ballModifier * levelModifier;
// This 'finalCatchValue' is not directly a probability yet. It needs scaling.
// A common scaling factor is related to 255 * (some value).
// For example, in some generations, a random number from 0 to 255 is generated and compared.
// Let's simplify and assume this 'finalCatchValue' represents a relative chance out of a maximum possible value.
// What is the maximum possible 'finalCatchValue'?
// Max BaseCatchRate = 255
// Max HP Multiplier = 1 (when HP = 0)
// Max Status = 2.5 (Sleep/Freeze)
// Max Ball = Say, 2.0 (Ultra Ball)
// Max Level = Say, 2.0 (if Level Modifier is 2.0)
// Max = 255 * 1 * 2.5 * 2.0 * 2.0 = 2550
// Let's define a "target" or "threshold" that represents a 100% catch chance under ideal conditions.
// This is where the formula gets very game-specific.
// For a simplified display: let's cap the probability at 100% and ensure it doesn't go below 0%.
// Let's assume the 'finalCatchValue' needs to be divided by a large number to get a probability.
// A common divisor might be around 1000 or more. Let's pick a heuristic divisor for display.
// If finalCatchValue is large, the probability should be high.
// Let's try to map this to a percentage directly.
// For simplicity, let's assume the calculated `finalCatchValue` represents the numerator of a fraction,
// and we need a denominator that makes sense.
// If we consider the maximum `finalCatchValue` to be around 2550 (as calculated above),
// then a probability would be `finalCatchValue / 2550`.
var estimatedProbability = (finalCatchValue / 2550.0) * 100; // Scale to percentage
// Ensure probability is within bounds [0, 100]
estimatedProbability = Math.max(0, Math.min(100, estimatedProbability));
// Display the result
resultDiv.innerHTML = "Estimated Catch Probability: " + estimatedProbability.toFixed(2) + "%";
resultDiv.innerHTML += "Factors considered:";
resultDiv.innerHTML += "
";
resultDiv.innerHTML += "
Pokémon Base Catch Rate: " + catchRate + "
";
resultDiv.innerHTML += "
HP Modifier: " + hpMultiplierStandard.toFixed(3) + " (based on " + pokemonHP + "/" + maxHP + " HP)