Mastering the Capture: Pokémon Scarlet & Violet Catch Mechanics
In the Paldea region, catching Pokémon follows a mathematical formula determined by several key factors. Whether you are hunting for a Shiny Pokémon, filling your Pokédex, or attempting to catch the ruinous quartet, understanding the math behind the ball throw can save you time and money.
The Catch Rate Formula in Gen 9
While the internal mechanics involve complex 16-bit integer math, the probability of a successful capture is primarily determined by four variables:
Base Catch Rate: Every species has a number between 1 and 255. A Pidgey has a rate of 255 (easy), while Koraidon and Miraidon have a rate of 3 (difficult).
HP Factor: This is one of the most significant variables. A Pokémon at 1 HP is roughly 3 times easier to catch than one at 100% HP.
Ball Multiplier: The type of ball matters immensely. A Quick Ball on turn 1 provides a 5x multiplier, whereas a standard Poké Ball is 1x. Dusk Balls are excellent in caves or at night (3x).
Status Multipliers: Never underestimate status conditions. Sleep and Freeze provide the highest bonus (2.5x), significantly better than Paralysis or Poison (1.5x).
Sandwich Powers
Pokémon Scarlet and Violet introduced Sandwich Powers (Meal Powers). The Catching Power buff directly multiplies your catch chance. Level 3 Catching Power essentially doubles your odds, which is vital for catching Pokémon in Beast Balls or other low-rate containers.
Critical Captures
As you complete your Pokédex, your chance of landing a "Critical Capture" increases. A Critical Capture bypasses the standard three-shake check and only requires one shake to succeed. While this calculator focuses on the standard probability, a completed Pokédex significantly boosts your long-term success rates.
Tips for Hard-to-Catch Pokémon
For legendaries with a Base Catch Rate of 3 (like Wo-Chien, Chien-Pao, Ting-Lu, and Chi-Yu):
Bring a Pokémon with False Swipe to safely reduce HP to 1.
Use Spore or Hypnosis to apply Sleep (2.5x bonus).
Use Dusk Balls if it is night (3x) or Timer Balls if the battle has lasted over 10 turns (4x).
Make a sandwich with Catching Power Level 2 or 3 matching the target's type.
function updateHPInput(val) {
document.getElementById('hpPercent').value = val;
}
function updateHPSlider(val) {
if(val > 100) val = 100;
if(val < 1) val = 1;
document.getElementById('hpSlider').value = val;
}
function calculateCatchRate() {
// 1. Get Inputs
var baseRate = parseFloat(document.getElementById('baseCatchRate').value);
var hpPercent = parseFloat(document.getElementById('hpPercent').value);
var ballMod = parseFloat(document.getElementById('ballType').value);
var statusMod = parseFloat(document.getElementById('statusCondition').value);
var sandwichMod = parseFloat(document.getElementById('sandwichPower').value);
// Validation
if (isNaN(baseRate) || baseRate < 1) {
alert("Please enter a valid Base Catch Rate (1-255).");
return;
}
if (isNaN(hpPercent) || hpPercent 100) {
alert("Please enter a valid HP percentage (1-100).");
return;
}
// 2. Core Logic (Gen 9 Approximation)
// Modified Catch Rate = Base * Ball * Status * ((3Max – 2Curr) / 3Max) * Sandwich
// HP Factor Logic: If Curr = P * Max (where P is 0.0 to 1.0)
// Factor = (3 – 2P) / 3
var p = hpPercent / 100;
var hpFactor = (3 – (2 * p)) / 3;
// Apply multipliers
var modifiedRate = baseRate * ballMod * statusMod * hpFactor * sandwichMod;
// Handle Master Ball logic
if (ballMod === 255) {
modifiedRate = 65535; // Guaranteed
}
var catchChance = 0;
var shakeCheck = 0;
// 3. Probability Calculation
if (modifiedRate >= 255) {
catchChance = 100;
shakeCheck = 100;
} else {
// Standard Formula approximation for display
// The exact game logic uses 16-bit integers and shake checks
// Formula: B = 65536 * (modifiedRate / 255)^0.25
// Probability of one shake success = B / 65536
// Total Capture Prob = (B / 65536)^4
// Calculating 'B' factor
var b = 65536 * Math.pow((modifiedRate / 255), 0.25);
// Probability of succeeding ONE shake check (0 to 1)
var pShake = b / 65536;
if (pShake > 1) pShake = 1;
// Total probability (4 successful shakes)
var pTotal = Math.pow(pShake, 4);
catchChance = pTotal * 100;
shakeCheck = pShake * 100;
}
// Clamp result
if (catchChance > 100) catchChance = 100;
// 4. Calculate Average Balls
// Expected value E = 1 / p
var avgBalls = 0;
if (catchChance > 0) {
avgBalls = 100 / catchChance;
} else {
avgBalls = "Infinite";
}
// 5. Display Results
var resultArea = document.getElementById('result-area');
var resChance = document.getElementById('resChance');
var resBalls = document.getElementById('resBalls');
var resShake = document.getElementById('resShake');
var resMessage = document.getElementById('resMessage');
resultArea.style.display = "block";
// Formatting numbers
var displayChance = catchChance.toFixed(2);
if (catchChance >= 100) displayChance = "100";
resChance.innerHTML = displayChance + "%";
resBalls.innerHTML = (typeof avgBalls === 'number') ? avgBalls.toFixed(1) : "∞";
resShake.innerHTML = shakeCheck.toFixed(1) + "% (Success per shake)";
// Contextual Message
if (catchChance >= 100) {
resMessage.innerHTML = "Guaranteed Catch! Go for it.";
resMessage.style.color = "#27ae60";
} else if (catchChance > 50) {
resMessage.innerHTML = "Great odds. Shouldn't take many tries.";
resMessage.style.color = "#27ae60";
} else if (catchChance > 20) {
resMessage.innerHTML = "Decent odds. Prepare a few balls.";
resMessage.style.color = "#f39c12";
} else {
resMessage.innerHTML = "Low odds! Apply status conditions or lower HP.";
resMessage.style.color = "#c0392b";
}
}