Total funds available in Big Blinds (e.g., $5000 at NL100 = 5000bb).
Expected winnings per 100 hands in Big Blinds.
Measure of variance (typically 80-120 for NLHE).
Probability of Going Broke
0.00%
function calculateRiskOfRuin() {
var bankroll = parseFloat(document.getElementById('bankrollBB').value);
var winRate = parseFloat(document.getElementById('winRate').value);
var stdDev = parseFloat(document.getElementById('stdDev').value);
var resultDiv = document.getElementById('riskResult');
var container = document.getElementById('resultContainer');
var analysisDiv = document.getElementById('riskAnalysis');
// Validation
if (isNaN(bankroll) || isNaN(winRate) || isNaN(stdDev)) {
alert("Please enter valid numbers for all fields.");
return;
}
if (bankroll <= 0 || stdDev <= 0) {
alert("Bankroll and Standard Deviation must be positive numbers.");
return;
}
container.style.display = "block";
// Logic for Non-Winning Players
if (winRate <= 0) {
resultDiv.innerHTML = "100%";
resultDiv.style.color = "#c0392b";
analysisDiv.innerHTML = "With a win rate of zero or less, ruin is mathematically inevitable over an infinite timeline.";
return;
}
// Calculation: RoR = e^(-2 * WinRate * Bankroll / StdDev^2)
// Since WR and SD are both per 100 hands, the units simplify directly.
// Formula derivation:
// mu (per hand) = winRate / 100
// sigma (per hand) = stdDev / sqrt(100) = stdDev / 10
// sigma^2 (per hand) = stdDev^2 / 100
// Exponent = -2 * (winRate/100) * Bankroll / (stdDev^2 / 100)
// Exponent = -2 * winRate * Bankroll / stdDev^2
var exponent = (-2 * winRate * bankroll) / (stdDev * stdDev);
var riskOfRuin = Math.exp(exponent);
// Convert to percentage
var riskPercent = riskOfRuin * 100;
// Formatting result
var displayText = "";
if (riskPercent < 0.01) {
displayText = "< 0.01%";
} else {
displayText = riskPercent.toFixed(2) + "%";
}
resultDiv.innerHTML = displayText;
// Dynamic Color Coding and Analysis
if (riskPercent < 1) {
resultDiv.style.color = "#27ae60"; // Green
analysisDiv.innerHTML = "Excellent. Your bankroll is very safe relative to your win rate and variance.";
} else if (riskPercent < 5) {
resultDiv.style.color = "#f39c12"; // Orange
analysisDiv.innerHTML = "Acceptable risk for aggressive bankroll management, but caution is advised.";
} else {
resultDiv.style.color = "#c0392b"; // Red
analysisDiv.innerHTML = "High risk. You should consider moving down in stakes or increasing your bankroll.";
}
}
Understanding Poker Risk of Ruin
Risk of Ruin (RoR) is a statistical concept used in poker to determine the probability that you will lose your entire bankroll before you double it or reach a specific financial goal. In the context of professional poker, it generally refers to the likelihood of going broke indefinitely assuming you continue to play with the same win rate and variance.
This calculator uses your win rate, standard deviation, and current bankroll size to estimate how safe your funds are. It assumes you do not move down in stakes when losing (static bankroll management), which represents the "worst-case" scenario for most players.
Key Inputs Explained
Bankroll (Big Blinds): The total amount of money you have set aside strictly for poker, expressed in Big Blinds (bb). To convert currency to bb, divide your money by the Big Blind of the game you play (e.g., $2000 at $0.50/$1.00 is 2000bb).
Win Rate (bb/100): Your edge in the game, measured in Big Blinds won per 100 hands. A sustainable win rate for a solid player is typically between 2 and 10 bb/100 depending on the stake and game type.
Standard Deviation (bb/100): A measure of the "swings" or volatility in your game. In No-Limit Hold'em, this is typically between 80 and 120 bb/100. PLO and Short Deck games will have significantly higher standard deviations.
The Mathematics of Ruin
The calculation is derived from the Brownian motion model of asset prices, adapted for gambling theory. The formula used for an infinite time horizon is:
RoR = e^(-2 * WinRate * Bankroll / StdDev²)
Where e is Euler's number (approx. 2.718). As you can see from the formula, doubling your win rate or quadrupling your bankroll has a massive exponential effect on reducing your risk of ruin, while an increase in standard deviation increases risk significantly.
Interpreting Your Results
Professional players typically aim for a Risk of Ruin of less than 1% or even 0.1%. If your result is above 5%, your bankroll is considered unstable, and you are statistically vulnerable to a downswing that could wipe out your funds entirely.
To reduce your Risk of Ruin, you can:
Move Down in Stakes: This effectively increases your bankroll in terms of Big Blinds and usually increases your win rate against weaker competition.
Improve Your Win Rate: Study and analyze your game to increase your bb/100.
Reduce Variance: Avoid marginal high-variance spots if your bankroll is threatened, though this should be balanced against maximizing Expected Value (EV).