Spin Math

What a slot session really costs, how likely you are to go bust, and what the casino should be giving you back.

Your session

Most people land between 400 and 600. Slower if you're chatting, faster on autoplay.
Game sets the return to player
Volatility how swingy the game is
Low: frequent small hits. High: long dry spells and big bonuses (Dragon Link, Buffalo Gold).

Your slip

Cost per hourwhat the house keeps, on average
Average session cost
A normal swingtwo out of three sessions land inside this
Bad night, 1 in 40
busted down, still playing walked out ahead

What you've earned in comps

How the numbers work

Every spin, the machine keeps a slice of the bet on average: the house edge, which is 100% − RTP. Your average cost is bet × spins × house edge. That same number is what the casino calls your theo (theoretical loss), and it's what they base comps on.

Swings come from volatility. We model a session's result as a bell curve with that average and a spread of volatility × bet × √spins, then ask how often the curve crosses your bankroll before time runs out. Real slot results are lumpier than a bell curve, so treat the bust chance as a guide, not a guarantee.

Return-to-player figures are typical published ranges, not a specific machine. The same game can be set differently from one casino to the next.