Enter bankroll size, average bet, RTP and volatility. The result is an estimate, not a promise of winnings or processing time.
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.
Methodology
The calculator uses the published deterministic formula shown on this page. Inputs are validated in application code; editors cannot change the formula.
FAQ
What does this result mean?
It is an educational estimate based only on the values entered. Actual gambling outcomes vary, and you should never chase losses.