Variance
The measure of how much results deviate from the expected outcome in the short term.
Variance (often called volatility in casino contexts) measures the swings in your results. A high-variance game produces bigger wins and bigger losses, while a low-variance game produces more consistent, smaller results.
Understanding variance is critical for bankroll management. Even with a positive expected value, high variance can wipe out your bankroll before the long-term math works in your favor. This is why professional gamblers size their bets carefully relative to their bankroll.
In slot machines, variance determines how frequently you win and how large the payouts are. High-variance slots pay out less often but with larger amounts. Low-variance slots pay out more frequently but in smaller amounts.
Related Terms
Standard Deviation
A statistical measure of how spread out results are from the average.
Bankroll Management
The practice of managing your gambling funds to minimize the risk of going broke.
Risk of Ruin
The probability of losing your entire bankroll, even with a positive edge.
Return to Player (RTP)
The percentage of wagered money a game returns to players over time.
Top Sportsbooks
Top-rated platforms reviewed by our editorial team