Pokemon Gen 2 Catch Rate Calculator

by

Pokémon Gen 2 Catch Rate Calculator

Gold, Silver, and Crystal Mechanics

Pidgey: 255, Lugia: 3
Poke Ball (1x) Great Ball (1.5x) Ultra Ball (2x) Master Ball (Auto)
None Asleep / Frozen (+10) Paralyzed / Poisoned / Burned (+5)
0%

Understanding Gen 2 Catch Mechanics

Catching Pokémon in Generation 2 (Gold, Silver, and Crystal) follows a unique formula that differs significantly from later games. In these titles, status conditions are added as a flat bonus to the calculation after multipliers are applied, making them extremely powerful for low-catch-rate Pokémon.

The Gen 2 Formula

The core of the calculation uses the following logic:

  • CatchValue (a) = ((3 * MaxHP – 2 * CurrentHP) * CatchRate * BallModifier) / (3 * MaxHP)
  • FinalValue = CatchValue + StatusBonus

If the FinalValue is 255 or higher, the Pokémon is caught automatically. If not, a random number between 0 and 255 is generated. If that number is less than your FinalValue, the capture is successful.

Critical Factors in Gen 2

  • HP Management: Lowering the wild Pokémon's HP to 1 increases the multiplier to roughly 3x.
  • Status Bonuses: Unlike Gen 3+, Gen 2 adds a flat bonus. Sleep and Freeze add 10 to the value, while Paralysis, Poison, and Burn add 5. For a legendary with a catch rate of 3, a +10 bonus is more impactful than an Ultra Ball!
  • Ball Bugs: Gen 2 is famous for bugs in special balls. For example, the Moon Ball only works on Pokémon that evolve with a Burn Heal due to a coding error, and the Love Ball only works if the Pokémon is the same species and same gender.

Examples

Pokémon HP Status Ball Approx. Chance
Lugia (Rate 3) 1 HP, Asleep Ultra Ball 7.4%
Snorlax (Rate 25) 50% HP, None Great Ball 9.8%
Ho-Oh (Rate 3) Full HP, None Poke Ball 0.4%
function calculateGen2Catch() { var baseRate = parseFloat(document.getElementById('baseRate').value); var ballMod = parseFloat(document.getElementById('ballType').value); var maxHP = parseFloat(document.getElementById('maxHP').value); var currentHP = parseFloat(document.getElementById('currentHP').value); var statusMod = parseFloat(document.getElementById('statusMod').value); // Validation if (isNaN(baseRate) || isNaN(maxHP) || isNaN(currentHP)) { alert("Please enter valid numbers for HP and Base Rate."); return; } if (currentHP > maxHP) { alert("Current HP cannot be higher than Max HP."); return; } // Gen 2 Special Case: Master Ball var selectedBallText = document.getElementById('ballType').options[document.getElementById('ballType').selectedIndex].text; if (selectedBallText.includes("Master Ball")) { displayResult(100, "The Master Ball never fails!"); return; } // Core Formula Logic // a = (((3 * MaxHP – 2 * CurrentHP) * Rate * BallMod) / (3 * MaxHP)) + StatusMod var hpFactor = (3 * maxHP) – (2 * currentHP); var calculationA = (hpFactor * baseRate * ballMod) / (3 * maxHP); var finalValue = Math.floor(calculationA) + statusMod; // In Gen 2, if finalValue is >= 255, it's 100%. // Otherwise, chance is (finalValue + 1) / 256 var percentage = 0; if (finalValue >= 255) { percentage = 100; } else { percentage = ((finalValue + 1) / 256) * 100; } // Clean up percentage if (percentage 100) percentage = 100; displayResult(percentage.toFixed(2), "Final Catch Value: " + Math.floor(finalValue)); } function displayResult(percent, detail) { var resultDiv = document.getElementById('catchResult'); var percentDiv = document.getElementById('catchPercentage'); var detailDiv = document.getElementById('catchDetail'); resultDiv.style.display = "block"; percentDiv.innerHTML = percent + "%"; detailDiv.innerHTML = detail; // Smooth scroll to result resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

Leave a Comment