Bankroll calculator
Pick a bet size, an RTP, a target multiplier and a starting bankroll. The calculator shows how many rounds your bankroll lasts on average, the probability of going bust, and the multiplier you need to break even over a long session.
How this works
The Spribe-style crash distribution gives a win probability per round of RTP ÷ target multiplier. At 97% RTP and a 1.5× target that is 0.97 / 1.5 = 64.7%. Win means the round crashes above your target; you collect target × bet minus your stake. Lose means the round crashes below; you lose your stake.
Expected value per round is (P_win × (target − 1) × bet) − ((1 − P_win) × bet). Over the long run this is always slightly negative (that is the house edge), so the calculator translates EV per round into how many rounds your bankroll survives on average.
The break-even multiplier shows the target that makes EV exactly zero. Anything below break-even gives the house a smaller edge, anything above gives a bigger edge. Useful for picking a target that matches your tolerance.
What this calculator is not
It is an expected-value model, not a simulator. Actual session length varies a lot round to round, especially with high targets where streaks of losses can wipe a bankroll faster than the average suggests. For variance estimates use the RTP simulator.
It also assumes you cash out at a fixed target every round. Most real players adjust the target during a session. That changes the math; the calculator gives you the steady-state baseline.