Lesson overview
Variance + Downswing Math
What being a 5BB/100 winner actually feels like over a sample
Read this introduction, then sign in to continue the full lesson and exercises.
Inside the full lesson
A 5BB/100 winner has a 30% chance of being on a 5-buy-in downswing at any given moment. Are you mentally ready for that?
In the full lesson, you work through this scenario with interactive examples.
Variance math is uncomfortable but unavoidable. Most players underestimate how often a winning player loses. The downswing distribution shows you the SHAPE of variance — not the average outcome but the tail of "what if I run bad for 20k hands?" This lesson is the math you need to NOT quit poker during a normal cold streak.
What you’ll learn
- The probability of N-buyin downswings as a function of win rate
- How sample size interacts with downswing probability
- Why "bad luck" stretches over 20k hands are statistical normalcy
From the full lesson
Variance basics — SD per 100 hands
Referenced activities and other examples are available in the full lesson after sign-in.
For 6-max NLHE 100bb cash, standard deviation per 100 hands is ~90-100 BB.
What that means:
- Over 100 hands, your result is win rate ± ~90 BB (one SD).
- Over 1k hands, your cumulative result is centered on 10x your win rate, with SD = 90 × sqrt(10) ≈ 285 BB.
- Over 10k hands, SD = 90 × sqrt(100) = 900 BB. So a 10k-hand sample for a 5 BB/100 winner has expectation +500 BB, SD 900 BB. Even a winning player can be down 400 BB at 10k hands without anything being "wrong."
From the full lesson
The 5BB/100 winner downswing table
Referenced activities and other examples are available in the full lesson after sign-in.
For a 5 BB/100 winner with SD = 90 BB/100, here's the probability of being on a downswing of size N:
| Downswing size | Probability of being on this downswing at any moment |
|---|---|
| 3 buy-ins (300 BB) | ~50% |
| 5 buy-ins (500 BB) | ~30% |
| 10 buy-ins (1000 BB) | ~12% |
| 15 buy-ins (1500 BB) | ~5% |
| 20 buy-ins (2000 BB) | ~2% |
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