*Calculations based on standard Gen VIII wild encounter mechanics.
Mastering the Catch in Pokémon Sword & Shield
The Gen VIII Catch Rate Calculator is designed to help trainers in the Galar region determine the exact likelihood of successfully capturing a wild Pokémon. Unlike simple probability games, the catch mechanics in Pokémon Sword and Shield use a complex formula involving HP, species rarity, ball type, and status conditions.
How the Gen VIII Catch Formula Works
In Generation 8, the game calculates a "Modified Catch Rate" (often denoted as a) whenever you throw a ball. This value determines how likely the ball is to shake and eventually seal the capture. The core factors are:
Species Rate: Every Pokémon has a base catch rate ranging from 3 (hardest, like Zacian or Zamazenta) to 255 (easiest, like Wooloo).
HP Factor: Lowering a Pokémon's HP is crucial. A Pokémon at 1 HP is roughly 3 times easier to catch than one at full health.
Ball Multiplier: Using the right tool for the job matters. An Ultra Ball provides a 2.0x multiplier, while a Dusk Ball at night provides a massive 3.0x multiplier (changed from 3.5x in previous generations, though often debated, standard calculators use 3.0x or 3.5x depending on context; in Sword/Shield dens it is highly effective).
Status Bonus: Status conditions are massive multipliers. Sleep and Freeze grant a 2.5x bonus, while Paralysis, Poison, and Burn grant 1.5x.
Why Use a Catch Rate Calculator?
Resource management is key, especially when hunting shiny Pokémon or Legendaries. Knowing that your chance is only 2% per throw might encourage you to use better balls or apply a status condition like Sleep. This calculator uses the standard Gen 3-8 formula logic:
False Swipe: This move leaves the target with exactly 1 HP, maximizing the HP factor in the equation.
The Gallade Strategy: Gallade can learn both False Swipe and Hypnosis, making it an excellent catcher for Gen VIII.
Critical Captures: Filling your Pokédex increases the chance of a "Critical Capture," where the ball only shakes once, significantly boosting success rates beyond what is shown in standard calculations.
Common Species Catch Rates
255: Caterpie, Bunnelby, Rookidee
190: Zigzagoon, Nickit
45: Onix, Steelix, Snorlax
3: Most Legendaries (Zacian, Zamazenta, Eternatus)
function calculateCatchRate() {
// Clear previous errors
var errorDiv = document.getElementById('errorMsg');
errorDiv.style.display = 'none';
errorDiv.innerHTML = ";
// Get Inputs
var speciesRate = parseFloat(document.getElementById('speciesRate').value);
var ballBonus = parseFloat(document.getElementById('ballType').value);
var maxHP = parseFloat(document.getElementById('maxHP').value);
var currHP = parseFloat(document.getElementById('currHP').value);
var statusBonus = parseFloat(document.getElementById('statusAilment').value);
// Validation
if (isNaN(speciesRate) || isNaN(ballBonus) || isNaN(maxHP) || isNaN(currHP) || isNaN(statusBonus)) {
errorDiv.innerHTML = "Please enter valid numbers in all fields.";
errorDiv.style.display = 'block';
return;
}
if (currHP > maxHP) {
errorDiv.innerHTML = "Current HP cannot be higher than Maximum HP.";
errorDiv.style.display = 'block';
return;
}
if (maxHP 255) a = 255;
// 2. Calculate Probability
var probability = 0;
if (a >= 255) {
probability = 1.0;
} else {
// Shake Check Calculation (Gen 3-8 Logic)
// b = 1048560 / sqrt(sqrt(16711680 / a))
// The probability of passing one shake check is b / 65536
// The catch happens if 4 shake checks pass.
var b = 1048560 / Math.sqrt(Math.sqrt(16711680 / a));
var pSingleShake = b / 65536;
// Probability of 4 successful checks
probability = Math.pow(pSingleShake, 4);
}
// Convert to percentage
var finalPercentage = probability * 100;
if (finalPercentage > 100) finalPercentage = 100;
if (finalPercentage < 0) finalPercentage = 0;
// Calculate Average Throws (Geometric Distribution: 1/p)
var avgThrows = 1 / probability;
if (probability === 0) avgThrows = "Infinity";
else if (probability === 1) avgThrows = 1;
else avgThrows = avgThrows.toFixed(1);
displayResult(finalPercentage, avgThrows, a);
}
function displayResult(percent, throws, modRate) {
var resultArea = document.getElementById('result-area');
var probSpan = document.getElementById('finalProb');
var throwsSpan = document.getElementById('avgThrows');
var modRateSpan = document.getElementById('modRate');
probSpan.innerHTML = percent.toFixed(2) + "%";
throwsSpan.innerHTML = throws;
modRateSpan.innerHTML = Math.floor(modRate); // Display integer part of 'a'
resultArea.style.display = 'block';
}