Bankroll arithmetic, in plain English
The house edge of a game is the slice of every bet the casino keeps on average — the inverse of the published RTP. At 96% RTP the edge is 4%, meaning every euro you put in returns ninety-six cents on average and the casino keeps four. Multiply that edge by your average bet and you have your expected loss per spin. Divide your starting bankroll by that number and you have the spins you can expect before the edge eats it.
Expected is not guaranteed. Volatility is the size of the swings around that average. A high-volatility slot might leave you with the full bankroll after fifty spins, then drain it in twenty — or never pay a meaningful hit at all in your session. We use volatility to scale a survival probability: the chance your bankroll outlasts the session you planned. For a recommended max bet we cap single-spin exposure at a small fraction of your starting roll so a deep losing streak does not end the night on spin three.
None of this predicts the next spin. It tells you what is reasonable to expect across a large number of them — useful for sizing bets to a bankroll, not for chasing losses.
