Smart players treat their bankroll like a budget, not a lottery ticket. Our free bankroll & session calculator estimates how long your money will last and the statistically expected cost of your session — so you can play within your limits.
Bankroll & Session Calculator
Plan how long your bankroll lasts and your statistically expected cost to play.
Based on the maths of RTP: expected cost = total turnover × (100% − RTP). Real results vary wildly due to variance. Only ever gamble what you can afford to lose. 18+ | begambleaware.org.
Bankroll survival curve
How long your bankroll is expected to last at this stake and RTP — the house edge alone, no luck.
The blue line is your expected balance over spins (average bet × house edge per spin). Real sessions swing above and below it; the marked point is where the edge alone exhausts a typical bankroll.
How the calculator works
It uses the maths behind every casino game: RTP (Return to Player) and its mirror image, the house edge. A 96% RTP slot has a 4% house edge, meaning that over the long run the game keeps about 4p of every £1 wagered. Multiply your total expected turnover by the house edge and you get your statistically expected cost.
The inputs
- Bankroll – the money you’ve set aside to play with (and can afford to lose).
- Average bet – your typical stake per spin or hand.
- RTP – the game’s published Return to Player percentage.
- Spins per hour – how fast you play; slots can exceed 500–800 spins/hour.
Why variance means your night will differ
The “expected cost” is a long-run statistical average across thousands of bets. In any single session, variance dominates: high-volatility slots can wipe a bankroll fast or deliver a big win, while low-volatility games drift closer to the expected figure. The calculator shows the mathematical baseline — not a prediction of your actual result.
Bankroll management tips
- Decide your bankroll before you play and never top up to chase losses.
- Match your stake to your bankroll — a common guide is 1–2% per spin for longer sessions.
- Set deposit and time limits using your casino’s responsible-gambling tools.
- Prefer higher-RTP games to reduce your expected cost over time.
Weighing up a bonus alongside your bankroll? Check the real playthrough with our Wagering Requirements Calculator.
18+. Only gamble what you can afford to lose. When the fun stops, stop. Help: BeGambleAware.org.
