Bankroll maths: how long will €100 actually last?

A simple formula, a calculator, and why volatility ruins every prediction.

The average cost of a spin is your stake multiplied by the house edge (100% minus RTP). On a 96% slot at €1 per spin, that's 4 cents per spin on average. So €100 "should" last about 2,500 spins.

It won't. Not because the maths is wrong, but because volatility means your balance swings far more than the average suggests.

A realistic rule

For a medium-volatility slot, plan for a session budget of at least 100 bets. For high volatility, 200–300 bets.

Try our bankroll calculator to see the numbers for your own stake and game.

Stop-loss and stop-win

Decide in advance when you'll stop — both if you lose your session budget and if you double it. Writing it down helps more than you'd think.