Slot Payback Percentages

15 July 2021

By John Grochowski

QUESTION: I don't get slot machine payback percentages. When a casino says its games pay 90 percent, why don't I actually get 90 percent. I put $20 in a penny slot, I'm not cashing out $18. More often than not, I'm cashing out zero. Isn't that zero percent?

ANSWER: Did you bet your entire $20 without a single payoff? That would be a zero percent payback.

But that's not what happens. You get payoffs of varying sizes while you play. Those go on the credit meter. Often, you'll make additional wagers with those credits.

If you get enough pays that you make $200 worth of wagers before you lose your stake, then you've lost $20 of $200 in wagers. You've lost 10 percent of your wagers, and the payback on that particular session is 90 percent even though you've cashed out nothing.

That aside, overall payback percentages on machines and throughout the casino are a jumble of winning sessions and losing sessions. When someone hits a $1,000 jackpot, that offsets a lot of small losses. The wins and losses together contribute to the payback percentage.

In sessions that don't include a winner big enough for you to walk away ahead of the game, your average payback percentage will be lower than the overall percentage. In sessions with big winners, your payback can be thousands of percent.

Both the big wins and the losses are part of normal probability. In the end, the odds of the game will drive results toward a targeted payback percentage. Some players will be happier than others, but the casino will collect its share.


QUESTION: I faced just this situation the other day after some tough times at blackjack and video poker.

I had $10 in my wallet. I was leaving, but it was a little past lunch time and I was hungry. The lunch buffet would cost me $15.

What I came up with was I went to roulette with a $5 minimum. I bet $5 on the first dozen and $5 on the third dozen. That way I had 24 numbers covered. The only numbers that could beat me were the second dozen or either of the zeroes.

I tried it. The number came up 31, so I won on the third dozen. I got $10 in winnings and kept my $5 bet, just enough for lunch. Otherwise, I'd have had to wait till I got home to eat, and I live about a 45-minutes away.

What do you think?

ANSWER: If you were willing to risk losing and wait 45 minutes to eat anyway, You could have done that without making the bets. Alternatively, you could have chosen a cheaper option and spent your $10 to eat on the road. This is all assuming you were unable or unwilling to buy lunch on a credit card.

By making the two dozens bets, you had 24 ways to win and 14 ways to lose. You had a 63 percent chance of winning and having just enough to cover your buffet.

Problem is, when you win with this system, you profit by only $5. On the 37 percent of spins where you lose, you lose $10.

Per 38 spins, you win $120 and lose $140. The house makes a $20 profit and has its usual 5.26 percent edge. You'll win more often than you lose, but lose more money than you win.

If the entertainment value of trying to win that last $5 toward lunch is worth it to you, that's your business. The empty-wallet risk is outside my comfort level.