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High-Denomination Slot Machines

8 March 2010

By John Robison


I consider myself a well educated gambler and recently found the Casino City Times site. I have read a large number of your responses to questions as well as asking some on the RNG and how it works. You provide excellent information and I wish that some people I see in the casino knew a little more about slots and the way they work. I am absolutely tired of hearing "that machine hit the jackpot 3 hours ago" or "that machine only pays when playing max credits". As much as I know the those statements have no effect on the outcome of my play it can sure change my attitude when playing, what a buzz kill. In any event thanks for all the information you provide.

Here is my question: I recently have changed my denomination to higher limit machines and I particularly enjoy playing Triple Gold or Triple Strike machines (same pay table, different name). Although I have not tracked the number of spins I have actually taken on these machines I estimate it's in the hundreds of thousands (I gamble a lot). So now instead of playing dollar machines, I play $5, $10, and $25 pretty regularly. I have found up till now I actually end up losing less money, I think primarily because for me walking away with an additional $200 is quite difficult but not so much with $2000 (not to mention a higher payback). You get the point.

So I have found this $10 two-coin Triple Strike. I have over a two-month period taken what I guess to be in the neighborhood of 25,000 spins on this machine. In the same instance on a dollar machine I would expect to hit three mixed triple sevens somewhere between 5 and 10 times. This particular $10 machine does pay the smaller prizes more often and I often can play for several hours on $500. I have read a previous question's answer to calculating a slot's payback percentage and how to roughly figure out the odds of hitting a particular prize. I have not completely done this but have done some rough estimates for the third reel, only to see how often I should get the third triple seven when I get the first two.

My best estimate is that a triple seven lands on the third reel about every 30-35 spins. That being said I have gotten the first two at least 150 times, probably more, and I would guess that just under half of those triple sevens are matching in color. Based on that I should have gotten the three triple sevens roughly 5 times. Do you think that my luck will catch up and I will have a streak where I hit them say 1 in every 15 times for a while or will I just have the 1 in 35 as intended by the programming? Also is it a common practice of casinos to use chips that pay lower prizes more frequently and big prizes less in higher denomination machines?

Thanks for the help,

Dear Kris,

Thanks for the kind words about my columns.

You ask a number of good questions and make some good points.

I'm a little surprised that you find you're losing less money on the high-denomination machines. The decrease in house edge going up in denomination from dollars rarely offsets the increase in risk by betting more per spin. Still, if you look at the virtual reel layouts of, say, a dollar Triple Strike and a $10 Triple Strike, you'll find that the chances of hitting any particular winning combination are pretty much the same on both machines -- but winning combinations pay 10 times as much on the ten-dollar machine. It's easier to hit for $200 on the $10 machine.

Now, as to whether you will hit three 7s more frequently in the future, machines never have to make up for what they have done in the past. Short-term aberrations from the probabilities we expect have less and less of an effect on a machine's numbers as the machine gets more play. A drop of food coloring in a gallon of water has much less of an effect than the same drop in a shot glass of water.

Finally, some casinos will use payback programs with high hit frequencies on their higher denomination machines. It's exciting to see high-denomination players easily hit amounts that are rarely hit on low-denomination machines. A $200 hit on a dollar machine is pretty high on the paytable, but a $200 hit on a $10 machine might be the for award double bars.

Best of luck in and out of the casinos,

Send your slot and video poker questions to John Robison, Slot Expert, at Because of the volume of mail I receive, I regret that I can't reply to every question.

John Robison
John Robison is an expert on slot machines and how to play them. John is a slot and video poker columnist and has written for many of gaming’s leading publications. He holds a master's degree in computer science from the prestigious Stevens Institute of Technology.

You may hear John give his slot and video poker tips live on The Good Times Show, hosted by Rudi Schiffer and Mike Schiffer, which is broadcast from Memphis on KXIQ 1180AM Friday afternoon from from 2PM to 5PM Central Time. John is on the show from 4:30 to 5. You can listen to archives of the show on the web anytime.

Books by John Robison:

The Slot Expert's Guide to Playing Slots