Calculate expected profit ranges and confidence intervals based on your win rate, standard deviation, and sample size to understand your realistic outcomes.
Your expected win rate in big blinds per 100 hands
Typical range: 60-120 BB/100 for cash games
Sample size for variance calculation
For converting results to currency (optional)
Quick-start with common scenarios
Monte Carlo simulation with 1,000 iterations
Your initial capital
Your expected advantage
Percentage of bankroll per bet
Total bets to simulate
Variance in poker measures how far your actual results can deviate from your expected results. Even with a positive win rate, short-term results are dominated by luck.
Standard Deviation (SD) quantifies your variance. With a win rate of $10/hr and SD of $80/hr, about 68% of your 100-hour samples will fall between$10 × 100 ± $80 × √100 = $1000 ± $800.
Sample size matters enormously. At 10,000 hands, a 5 BB/100 winner has about a 30% chance of being down money. At 100,000 hands, this drops to ~5%. Professional conclusions require 200,000+ hands.
Confidence intervals tell you the range where your results should fall:
Variance measures how much your actual results deviate from expected results. Even if you're a winning player averaging $25/hour, you might have sessions losing $500 or winning $800 due to variance.
Standard deviation (SD) measures the spread of your results. A typical cash game player has SD of 70-90 BB/100. Higher SD means more swings. About 68% of your samples will fall within ±1 SD of your expected value.
You never fully 'beat' variance, but at 100,000+ hands your results become statistically significant. At 30,000 hands, confidence intervals are still very wide. Professional conclusions require 200,000+ hand samples.
That's variance in action. A player winning at 5 BB/100 might actually be down 20+ buyins after 50,000 hands and still be running normally. The confidence intervals show the realistic range of outcomes.
Yes. Tight-aggressive styles have lower variance (SD ~70 BB/100). Loose-aggressive styles and players who bluff frequently have higher variance (SD ~100+ BB/100). Tournament players face extreme variance.