Slot machine payback

Okay so as I understand it, slot machines come from the factory with a chip installed to control the odds and the payback. Usually like 93% or 95% or 97.135456% or something. And there are Gaming laws that govern how low you can order it with, and the payback is checked by the board.

I was curious about the very common slots that don’t have a linear payback on the jackpot.

1 coin jackpot = 1000
2 coin jackpot =2000
3 coin jackpot = 5000

or something similar on a machine with a payback of X. Obviously the Jackpots are fairly rare, but they do effect payback over long periods of time.

So does the machine take the number of coins into consideration when generating it’s sequence? Are they programmed to return X if you only play one coin, or just over the expected tendency of the players. What I mean is that the bonus for a three coin Jackpot would push a three coin player slightly over X, and 1 and two coin players would be just under X to arrive at the overall X. Or do they have to program them so any pull has an expectation of X, which would mean wining combinations more often over time for the 1 and 2 dollars, to make up for the three coin jackpot bonus.

IIRC we have a doper who works for one of the casino game manufacturers but in essence, its just a random number generator with expected payout odds over time. A given machine could lose money over the short haul but over a couple years they pay off. Also remember its not just one slot machine so if you have 100 machines and 1 hits a big jackpot you still might be in the black on revenues from all of the losers on other machines.

In Missouri minimum payback is (or was) set by the gaming commission at 90% – but I don’t know whether that was per machine or collectively all the machines in a casino.

This led to casinos advertising their paybacks. “We have 95%!” So what? We have 97%!" and on and on.

It is funny when they put it straight out there as their best enticement and people still don’t get it.

No, no, you’ve got it all wrong; we get it just fine. Most people lose when they gamble, everybody knows that. So to balance things out, a few people have to win big. I obviously fall into the latter category.


IANA slot machine expert, but I read a book about this last year. The following is all IIRC:

In modern slot machines, chips do not have a factory preset payout. The individual casino programs the desired payout on each machine.

I think there’s a basic misunderstanding of progressive slots here. The payout rate you see on fliers and billboards (“Loosest slots in Vegas! 98% payout!”) usually from the highest payout table on a particular slot machine. I.e. if you put in one credit, your payout is 90%, two credits is 94% and maximum credits is 98%. They never advertise the actual pay tables of less than the maximum number of credits. As you suspect, this stems from the fact that hitting the “rarer jackpots” has a lower payout. The actual likelihood of hitting a particular combination is identical no matter how many credits you put in. The only thing you change by putting in a smaller bet is that you get a smaller payout; not a smaller chance of getting that payout.

Further complicating this is the fact that (in Nevada, at least) every slot machine a given bank of machines does not need to meet the advertised payout. If you’re in a casino and you see a bank of machines with a big rotating sign over them that says “99% Payout!!” then odds are, only one of those machines has that payout table – and even then, that payout is only for its maximum bet. The other machines are significantly lower.

To answer one part of the question, yes it does change your odds to bet more coins but you have to watch out. The best odds are not usually with the maximum bet but one just below the top. This is the same with Keno, where the odds are printed out more plainly. Study a keno card and you will get the idea, there is a steady progression that stop just before the top bet. I presume this is because they know people will see the trend and just asume the top is the best.