Calculate your probability of encountering a Shiny Pokémon
Gen 6-9 Base Rate (1/4096)
Gen 6-9 + Shiny Charm (1/1365)
Masuda Method (Gen 6+) (1/683)
Masuda Method + Shiny Charm (1/512)
Gen 2-5 Base Rate (1/8192)
SV Sandwich Power Lv3 (1/1024)
SV Sandwich Power Lv3 + Charm (1/683)
SV Outbreak (60+ KOs) (1/1365)
SV Outbreak (60+) + Charm (1/819)
SV Outbreak (60+) + Charm + Sandwich 3 (1/512)
Dynamax Adventures (with Charm) (1/100)
Let's Go Chain 31+ (1/341)
Chain Fishing (Max Chain) (1/96)
Custom Odds (1 in X)
Calculation Results
Base Probability:1 in 4096
Success Chance (in 0 tries):0.00%
Did you reach odds?No
Insight: To reach a 90% probability of finding a shiny with these odds, you would need approximately 0 encounters.
function toggleCustomInput() {
var method = document.getElementById('huntingMethod').value;
var customGroup = document.getElementById('customOddsGroup');
if (method === 'custom') {
customGroup.style.display = 'block';
} else {
customGroup.style.display = 'none';
}
}
function calculateShinyOdds() {
// Inputs
var methodValue = document.getElementById('huntingMethod').value;
var customOddsInput = document.getElementById('customOdds').value;
var encountersInput = document.getElementById('encounters').value;
// Element Output References
var resultDiv = document.getElementById('shinyResult');
var baseProbDisplay = document.getElementById('baseProbDisplay');
var encountersDisplay = document.getElementById('encountersDisplay');
var percentChanceDisplay = document.getElementById('percentChance');
var oddsStatusDisplay = document.getElementById('oddsStatus');
var probBarFill = document.getElementById('probBarFill');
var ninetyPercentDisplay = document.getElementById('ninetyPercent');
// Logic Initialization
var denominator = 0;
var encounters = parseFloat(encountersInput);
// Validation
if (!encounters || encounters < 0) {
alert("Please enter a valid number of encounters.");
return;
}
// Determine Base Odds
if (methodValue === 'custom') {
denominator = parseFloat(customOddsInput);
if (!denominator || denominator = 1) = 1 – (1 – p)^n
var p = 1 / denominator;
var chanceOfFailure = 1 – p;
var chanceOfFailureAfterN = Math.pow(chanceOfFailure, encounters);
var successProbability = 1 – chanceOfFailureAfterN;
var percentage = successProbability * 100;
// Calculate encounters needed for 90% confidence
// 0.10 = (1 – p)^n -> ln(0.10) = n * ln(1-p) -> n = ln(0.10) / ln(1-p)
var encountersFor90 = Math.log(0.10) / Math.log(1 – p);
// UI Updates
resultDiv.style.display = 'block';
baseProbDisplay.innerHTML = "1 in " + Math.round(denominator);
encountersDisplay.innerHTML = encounters;
percentChanceDisplay.innerHTML = percentage.toFixed(2) + "%";
probBarFill.style.width = (percentage > 100 ? 100 : percentage) + "%";
ninetyPercentDisplay.innerHTML = Math.ceil(encountersFor90).toLocaleString();
// Status Logic
if (encounters >= denominator) {
oddsStatusDisplay.innerHTML = "Yes (Over Odds)";
} else {
oddsStatusDisplay.innerHTML = "No (Under Odds)";
}
}
Understanding Shiny Rates and Probability
Shiny hunting is a beloved mechanic in the Pokémon franchise, offering players the chance to capture rare, alternately colored versions of their favorite creatures. However, the mathematics behind these encounters can often be counter-intuitive. This Shiny Rate Calculator helps you determine exactly how likely you are to find a shiny Pokémon based on your specific game, method, and number of attempts.
How Shiny Odds Work
In most modern Pokémon games (Generation 6 through Scarlet/Violet), the base odds of encountering a shiny Pokémon are 1 in 4096. This does not mean that if you encounter 4096 Pokémon, you are guaranteed a shiny. Instead, it works like a dice roll: every single encounter is an independent event with a 1/4096 chance of success.
The "Over Odds" Fallacy
Many hunters believe that once they reach the denominator number (e.g., 4096 encounters), they "deserve" a shiny. Statistically, however, reaching the exact odds number only gives you approximately a 63.2% chance of having found a shiny by that point. This calculator uses the binomial distribution formula 1 – (1 – p)^n to provide the accurate probability.
Common Methods and Rates
Various items and methods can drastically improve your odds. This calculator includes presets for the most popular hunting strategies:
Shiny Charm: A key item usually obtained by completing the Pokédex. It generally adds two extra rolls to the RNG check, tripling your odds to roughly 1/1365.
Masuda Method: Breeding two Pokémon from different real-world languages. This increases the odds significantly, often to 1/683 (or 1/512 with the Shiny Charm).
Mass Outbreaks (Gen 9): In Scarlet and Violet, defeating 60+ Pokémon in an outbreak boosts the shiny rate for that specific outbreak species.
Sandwich Powers: Using Sparkling Power Lv. 3 sandwiches in Gen 9 provides one of the highest boosts available.
How to Use This Calculator
Select Method: Choose the game and method you are using (e.g., "Masuda Method + Shiny Charm").
Input Encounters: Enter the number of eggs hatched or wild Pokémon encountered so far.
Analyze Results: The calculator will show you the percentage chance that you should have found a shiny by now. If the percentage is high (e.g., over 90%) and you still haven't found one, you are statistically unlucky for this hunt!
Use this tool to manage your expectations and track your progress during your shiny hunting adventures.