RTP & Volatility Calculator
Work out how long your bankroll survives at a given bet size, RTP and spin rate — and see the spread between an unlucky and a lucky scenario.
Fill in bankroll, bet size, spins per hour, RTP and volatility to see how long your bankroll survives.
This is based on the statistically expected outcome and a simplified volatility model. Actual sessions are governed by chance and can end both better and worse than the expected value and the range above. Play responsibly.
RTP (return to player) only tells you what happens on average over a very large number of spins. This calculator connects RTP with your bankroll, bet size and spin rate to show how long the money statistically lasts — and just as importantly, how much volatility (variance) affects what actually happens in a single session.
How we calculate how long your bankroll lasts
Expected loss per hour = bet × spins per hour × (1 − RTP). Expected spins until the bankroll is gone = bankroll / (bet × (1 − RTP)). With a bankroll of 1000, a bet of 10 and an RTP of 96%, that's 1000 / (10 × 0.04) = 2500 spins on average.
That average hides the fact that individual sessions are governed by the game's variance, not just the house edge. A low-volatility game pays out more evenly — results stay close to the average. A high-volatility game can produce long losing streaks followed by a rare large win, so a single session can swing wildly in either direction from the average.
That's why the calculator also works out an unlucky and a lucky scenario (±1 standard deviation) based on the volatility level you choose. The higher the volatility, the wider the gap between the two scenarios — which is exactly the point: at high volatility, the expected value tells you very little about what will actually happen to you.
Worked example
Say you have a bankroll of 1000, bet 10 per spin on a slot with 96% RTP at medium volatility, spinning at 400 spins an hour. Expected loss per hour is 10 × 400 × 0.04 = 160, and on average the bankroll lasts 2500 spins — around 6.25 hours of play.
But at medium volatility, the spread shows an unlucky run could empty the bankroll after just a few hundred spins, while a lucky run could stretch to tens of thousands of spins before it's gone. Both are entirely possible outcomes for the same deposit — which is why a single "expected" number never tells the whole story.
Frequently asked questions
Does "expected spins" mean I'll play for exactly that long?
No. It's a statistical average, not a forecast for your specific session. The game's variance means the actual playing time almost always differs from the average — sometimes by a lot, which is exactly what the range (unlucky/lucky scenario) above is meant to show.
Why does volatility matter if the RTP is the same?
RTP only tells you what stays with the player on average over a very large number of spins — it says nothing about how evenly or unevenly that result is spread out. Two games can share the exact same RTP but have completely different volatility: one pays out small amounts often, the other rarely but big. The higher the volatility, the more a single session diverges from the RTP average.
Where can I find a specific game's actual volatility?
Most game providers list a volatility or variance rating (often low/medium/high, sometimes on a 1–5 scale) in the game's rules or info screen. Use that stated value instead of a general assumption when you want a more accurate estimate for that particular game.
