Pokemon Gen 3 Catch Rate Calculator

Gen 3 Pokemon Catch Rate Calculator

Legendaries: 3, Common: 255

Poke Ball (1.0x) Great Ball (1.5x) Ultra Ball / Safari Ball (2.0x) Net Ball / Repeat Ball (3.0x) Dive Ball (3.5x) Timer Ball (Max 4.0x) Master Ball (Auto-Catch)

None (1.0x) Sleep or Freeze (2.0x) Paralyze, Poison, or Burn (1.5x)

Catch Probability

0%

function calculateGen3Catch() { var mHP = parseFloat(document.getElementById('maxHP').value); var cHP = parseFloat(document.getElementById('currentHP').value); var baseRate = parseFloat(document.getElementById('baseCatchRate').value); var ballMod = parseFloat(document.getElementById('ballBonus').value); var statusMod = parseFloat(document.getElementById('statusBonus').value); if (isNaN(mHP) || isNaN(cHP) || isNaN(baseRate) || mHP mHP) cHP = mHP; // Master Ball edge case if (ballMod >= 255) { document.getElementById('resultArea').style.display = 'block'; document.getElementById('catchPercentage').innerHTML = "100.00%"; document.getElementById('shakeProbability').innerHTML = "The Master Ball never fails!"; return; } // Gen 3 Catch Rate Formula: // a = (((3 * MaxHP – 2 * CurrentHP) * CatchRate * BallModifier) / (3 * MaxHP)) * StatusModifier var a = (((3 * mHP – 2 * cHP) * baseRate * ballMod) / (3 * mHP)) * statusMod; var catchProb; if (a >= 255) { catchProb = 100; } else { // In Gen 3, the actual probability uses 4 shake checks. // b = 65536 / (255/a)^0.25 // Probability = (b / 65536)^4 // Simplified approximation for standard users: var b = 65535 / Math.pow(255 / a, 0.25); catchProb = Math.pow(Math.floor(b) / 65536, 4) * 100; } document.getElementById('resultArea').style.display = 'block'; document.getElementById('catchPercentage').innerHTML = catchProb.toFixed(2) + "%"; var avgBalls = (catchProb > 0) ? (100 / catchProb).toFixed(1) : "Infinite"; document.getElementById('shakeProbability').innerHTML = "Estimated average " + avgBalls + " balls required for success."; }

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How the Gen 3 Catch Rate Logic Works

Generation 3 Pokemon games (Ruby, Sapphire, Emerald, FireRed, and LeafGreen) introduced a specific mathematical formula to determine whether a Pokemon is caught or if the ball shakes and breaks. Unlike later generations, the Gen 3 formula relies heavily on the a-value and four independent random checks.

The Catch Rate Formula (The "a" value)

The game first calculates a value called a. If a is 255 or higher, the Pokemon is caught instantly. The formula is:

a = (((3 * Max HP – 2 * Current HP) * Catch Rate * Ball Bonus) / (3 * Max HP)) * Status Bonus

Key Factors Explained

• Max HP & Current HP: The lower the Pokemon's current HP relative to its maximum, the higher the catch chance. Getting a Pokemon to 1 HP (using moves like False Swipe) is the most effective strategy.
• Base Catch Rate: Every Pokemon has a hidden "catch rate" value between 1 and 255. Legendaries like Rayquaza or Kyogre have a catch rate of 3, while common Pokemon like Zigzagoon have 255.
• Ball Bonus: Different balls provide different multipliers. A standard Poke Ball is 1.0x, while an Ultra Ball is 2.0x. In Gen 3, Net Balls are particularly powerful against Water and Bug types (3.0x).
• Status Bonus: Applying a status condition is crucial. Sleep and Freeze provide a 2.0x multiplier, while Paralysis, Poison, and Burn provide a 1.5x multiplier.

Calculation Example: Catching Rayquaza

Imagine you are trying to catch Rayquaza in Emerald version:

1. Stats: Max HP: 200, Current HP: 1.
2. Conditions: Rayquaza is asleep (2.0x bonus) and you use an Ultra Ball (2.0x bonus).
3. Base Catch Rate: 3.

The math: a = (((3*200 - 2*1) * 3 * 2.0) / (3*200)) * 2.0.
a = ((598 * 6) / 600) * 2 = 11.96.
Because 11.96 is much lower than 255, the game performs "shake checks." The actual probability of catching Rayquaza under these ideal Gen 3 conditions is approximately 8-9% per Ultra Ball thrown.

Gen 3 Specific Tips

If you are playing FireRed or LeafGreen, remember that the Safari Ball has a fixed bonus of 2.0x, the same as an Ultra Ball. However, you cannot weaken Pokemon in the Safari Zone, so you must rely on the "Throw Bait" or "Throw Rock" mechanics which alter the catch rate and flee rate respectively.

For long battles, the Timer Ball becomes your best friend. In Gen 3, after 30 turns, the Timer Ball reaches its maximum multiplier of 4.0x, making it twice as effective as an Ultra Ball.