The probability of losing your entire bankroll, even with a positive edge.
Risk of ruin calculates the probability that you'll go completely broke given your edge, bet size, and bankroll. Even profitable bettors face risk of ruin if they bet too large a percentage of their bankroll.
The key insight is that risk of ruin drops dramatically as your bankroll grows relative to your bet size. A bettor with a 5% edge risking 10% of their bankroll per bet has a much higher risk of ruin than one risking 2% per bet with the same edge.
This is why bankroll management is not optional for serious gamblers. The math is clear: without proper bankroll sizing, even a winning strategy can result in going broke.
A bettor with a $5,000 bankroll flat-betting $250 (5% per bet) at a 55% win rate on -110 spreads faces a risk of ruin near 3% over 1,000 bets. Cut the bet size to $100 (2%) and risk of ruin collapses below 0.1% — the same edge, dramatically safer.
Double the stake to $500 (10% per bet) and ruin risk explodes past 20% even with the same winning edge, because variance swings eat the bankroll before the edge plays out. A card counter with a 1% edge at a Vegas blackjack table needs roughly 400 max bets in reserve to keep ruin risk under 5%. The formula rewards discipline: smaller units, bigger edges, and longer sample sizes all compound in the bettor's favor.
<p>A bettor with a <strong>$5,000 bankroll</strong> flat-betting $250 (5% per bet) at a 55% win rate on -110 spreads faces a risk of ruin near <strong>3%</strong> over 1,000 bets. Cut the bet size to $100 (2%) and risk of ruin collapses below 0.1% — the same edge, dramatically safer.</p><p>Double the stake to $500 (10% per bet) and ruin risk explodes past 20% even with the same winning edge, because variance swings eat the bankroll before the edge plays out. A card counter with a 1% edge at a Vegas blackjack table needs roughly <strong>400 max bets</strong> in reserve to keep ruin risk under 5%. The formula rewards discipline: smaller units, bigger edges, and longer sample sizes all compound in the bettor's favor.</p>
The practice of managing your gambling funds to minimize the risk of going broke.
A formula for calculating the optimal bet size to maximize long-term bankroll growth.
The measure of how much results deviate from the expected outcome in the short term.
A standardized bet size used to track performance, typically 1-2% of your bankroll.
The probability of losing your entire bankroll, even with a positive edge.
<p>A bettor with a <strong>$5,000 bankroll</strong> flat-betting $250 (5% per bet) at a 55% win rate on -110 spreads faces a risk of ruin near <strong>3%</strong> over 1,000 bets. Cut the bet size to $100 (2%) and risk of ruin collapses below 0.1% — the same edge, dramatically safer.</p><p>Double the stake to $500 (10% per bet) and ruin risk explodes past 20% even with the same winning edge, because variance swings eat the bankroll before the edge plays out. A card counter with a 1% edge at a Vegas blackjack table needs roughly <strong>400 max bets</strong> in reserve to keep ruin risk under 5%. The formula rewards discipline: smaller units, bigger edges, and longer sample sizes all compound in the bettor's favor.</p>
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