• Average Slot Machine Odds
• How To Play Slots Odds
• Can Casinos Change The Odds On Slot Machines Real Money
• Slot Machines Odds Of Winning

The first time I saw people use member cards for slot games, I didn’t know what they were. I asked the man sitting next to me and he explained a few details about the rewards club. But he wasn’t using a card himself.

Standalone slot machines are those which are most often found in older casinos, but are technically slot machines including within their cabinets the ability to set and provide odds of winning with a random number generator. A workforce of slot mechanics adjust the odds of winning periodically as directed by the casino operator.

When I asked him why, he said he once had a card but stopped winning when he played with the card. He thought the casino was monitoring his playing and adjusting the slot game results.

This rumor has circulated both online and offline for many years. It’s normal for people to hear something repeatedly and wonder if there is truth to it. But I’ve never found any proof that casinos can change the way slot games play by flipping a switch.

What makes it difficult to combat this idea and other rumors about slot machines is the many different markets where you find them. Slot machine games are regulated by each country. Complying with different regulations may mean that a slot maker must change how its games work.

The clearest example I can give is how slot games are decided in the United States. Class II slot games decide the outcome on the basis of one random number then configure the display to match that result. Class III games use several random numbers to control the reels.

How Modern Slot Machine Games Work

There aren’t many physical slot games left. They’re all electronic now, and the electronic machines use random number generator chips to decide results.

But there is more involved than just generating a random number. The “slots” in the slot games are spaces on reels. The computers now simulate these reels.

Former and current slot machine manufacturing employees answer questions about game design on several websites including Quora. This answer was posted in September 2014, and it explains how the simulated reels are managed by software.

The programs to simulate the reels and assign the random numbers are etched into ROMs, Read-Only Memory chips. These ROMs must be physically changed by a technician to change how the game payout percentages work.

Legitimate Online Casino Operators Lease Games From Service Providers

There are over 2,000 online casinos. It’s impossible to be sure about how they all manage their slot games. But what is known about the most popular casinos is that they don’t run their slot games from their own servers.

Instead the online casinos lease game services from secure data centers. These gaming platforms are run by companies like Blue Ocean and EveryMatrix. Some of the game design companies also run their own servers, leasing resources to online casinos.

Although it would be simple for online gaming companies to switch things up, they would risk losing independent certifications if they allowed the games to be rigged.

There’s no need for casinos to adjust the percentages. They can order the percentage breakouts for house edge and return to player that they want to offer. This way, they maintain competitiveness and support long-term profitability.

Many Games Publish the Theoretical Return to Player

Some slot games include the theoretical return to player in their help screens.

If the players see that RTP has been adjusted downward, they can play elsewhere. If players only suspect that the RTP has been adjusted without proper notification, they might still leave.

Casinos need players. The best strategy to grow their customer base is to keep game rewards high enough to make the risk worthwhile.

Some Governments Regulate Return to Player Percentages

Licensed gaming casinos must comply with local laws governing their businesses. Some countries provide more regulation than others.

In the United States, commercial land-based casinos are regulated by their states. However, Native American casinos are mostly regulated by the tribal governments that own them. Each jurisdiction has the authority to set minimal RTP percentages to ensure the casinos don’t make too much money.

The 1988 Indian Gaming Regulatory Act creates the legal framework used by tribes to protect their traditional gaming activities from state regulatory laws. The act also defines the three classes of gaming and how they are to be regulated.

Class II games are regulated by the tribes but only in states that allow any kind of gaming. Only Class III games are subject solely to state regulation.

True slot machine games are Class III games. Native American casinos offer Class II bingo games that are made to look like slot games. The game cabinets must display the casino bingo games that are used to determine wins.

Class II slot machines may have reels and bonus games but they’re not really slot machine games as defined by federal law.

How Do You Determine the Odds That a Slot Game Pays?

Casinos may or may not be required to declare the return to player for their slot games. Some casinos place a plate or sticker on their slot games with a notice. Other casinos leave it to the game help screens (thus, the manufacturers) to inform players.

The games’ odds may be reported as a theoretical RTP percentage, but they could also be reported as a ratio, similar to the way lottery games declare chances of winning a prize. Either way, these games don’t have to tell you how often to expect to win a prize of any amount.

Some players merely judge the looseness of slot games by how much money they win or how often they win as they play the games.

Some players judge the looseness of slot games by how popular they appear to be. This observational strategy assumes that the crowd knows more than the individual.

One of my friends tells me he only plays slot games with low jackpots. His reasoning is that players need to lose less money for someone to win $10,000 than for someone to win $20,000.

Slot Machines May Have Programmed Payout Limits

In another post on Quora from 2016, someone claimed to have industry experience in the Caribbean.

In his post, he said that a machine won’t pay more than it has accumulated after the first month of operation. That first month establishes the limit based on the profit the machine made.

The system is designed to be random within a range of percentages. The software decides when and how much to pay but won’t go over the monthly limit.

It should be obvious that this limit could be reset.

The Games Are Designed to Be as Random as Possible

People who design and repair slot machine games express much trust in the random number generator chips these games use. The RNGs, as they are called, use the latest available algorithms at the time they are manufactured.

Math has not yet progressed to the point where truly random numbers can be generated. Mechanical devices require input from an outside source to be truly random.

The way slot game designers handle this limitation is they design the chips to generate thousands of random numbers every second. The random numbers each take a turn at being available for use by the game.

Because of the percentage payouts and internal limits they use, slot machine games don’t have to be reprogrammed to improve casino profits. Everything is designed to run with as little intervention as possible.

And that is better for the casino because the more they can intervene in a game’s function, the more likely they’ll face regulation over that intervention.

Casino game techs often say that replacing chips in slot machines must follow a special procedure (in the United States). They are closely monitored and every part must be accounted for. So, it’s less expensive for casinos if they don’t tweak the games.

Conclusion

An honest casino doesn’t need to control who wins at a slot game. They already control who can play a slot game. They can ask anyone to leave for any reason.

Naturally, casinos don’t do that. Instead. they purchase gaming systems that are designed to create an entertaining experience for patrons while legally retaining a profitable percentage of wagers.

No matter how much one’s frustration tempts a player into wondering about Big Brother Casino tweaking the game, it’s more profitable for the casino to let nature take its course.

No, the machine does not have a huge element table of over two billion elements. The random number generators choose each number once in the cycle using mathematical algorithms and do not need to keep track of which numbers were already chosen. Regarding the pause, it has nothing to do with how much it is going to pay. I think the game does some internal auditing from time to time. There is no such thing as hot and cold cycles with slot machines. The ups and downs are just normal random variation.

These are just random events. The laws of probability dictate that some days will be dry with a few big winners and others will have a lot of lower payouts. Most days will have a balanced mix and these days are always the first forgotten by the player. There is no switch the casino is throwing to alter the mood of their machines. I tend to think you're just remember what you want to in order to substantiate your theory.

No, this does not happen. How much the slot machine pays is determined by a microchip called an EPROM, which is generally left alone. To change it, at least in Nevada, the casino would have to get permission from the gaming authorities. Even without permission, they would have to open up each machine and change the EPROM by hand.
I speculate that the reason for what you observed about all the machines on a carousel getting hot at the same time is due partially to chance, partially selective memory, and partially to a snowball effect where players will gravitate to an area where they hear a lot of winning and simply add to the number of wins because of more players.

Your explanation of virtual versus physical slot machine reels was most informative.

1. Given the random number generator stops on a virtual Cherry say, how does the machine make the physical reel stop on a visible cherry? I mean technically speaking.
2. Does this explain how pachinko machines from Japan can electronically alter payout percentages without altering the physical reel symbols?
3. Suppose the machine decides its time for a BAR, the only BAR on the third reel, just as one passes the pay-line. Does it let the reel go one full turn and catch it on the next go-round?
4. Suppose a physical reel stops on a paying combination by mistake, i.e. a symbol other than the virtual one pre-ordained. What happens then?

Thanks much.

Let me answer each question individually.

1. It is just programming code that dictates to the machine that if the virtual reel stops on a cherry to make the actual reel stop on a cherry. There are actual notches on the reels which may help the machine to stop in the right place. If you peer through the glass at and angle you can sometimes see these notches. However, I am not an engineer and am not sure exactly how the machine knows to stop at just the right moment. It just take it for granted that it can.
2. Theoretically, the casino could change the payout on a slot machine with just a remote control. The remote control could tell the machine to use any previously programmed virtual reels. Practically speaking, the major casinos need to get approval from the gaming authorities to change the payback of a machine. If they did get such authorization all a slot technician has to do is replace a chip inside the machine, known as an e-prom. This happens infrequently and would not warrant the expense of a remote control.
3. It seems to me the reels spin at least several times before stopping.
4. In the unlikely even that happened, then I think it would trigger a malfunction and the bet would be voided.

I will say that for class 3 slots by major slot makers like IGT, Bally, and Williams do not resort to these sort of tricks. With respectable slot machines every play has the exact same probability of winning. If you don't believe me then why don’t you go from machine to machine playing each one for half an hour.

Not often. Contrary to popular myth the casinos don’t tighten the machines on weekends or whenever it is busy. Here in Las Vegas the casinos have to fill out a form every time they change the percentage on each game. Most slot managers I have spoken with have a policy on what coinage is set to what return. I tend to think the most likely reason to change the percentage would a change in ownership and/or management, which do not happen often.

Average Slot Machine Odds

No. Neither the amount you put in nor the denomination affects the odds. The same is true of slots.

From what I hear anything you can configure at the machine you can configure remotely through the server. This would include the theoretical return percentage. However most casinos report that changing the theoretical return of a slot machine necessitates a lot of paperwork.

Even if it were effortless to move the slot machine return up and down, it strikes me as a conspiracy theory to think the casinos would do that on a player by player basis. Living here in Vegas, I hear all kinds of theories about the lengths the casinos go to in order to win, like pumping in oxygen and playing a subsonic mantra that says 'lose lose lose.' These are just urban legends. Most casinos correctly believe that if you give the player a good experience and a fair gamble then he will keep coming back. As they say, you can only slaughter a sheep only once, but you can shear it many times. (My webmaster, Michael Bluejay, who is a vegetarian, tried to get me to use this analogy instead: 'You can seize all of a sheep’s money only once, but you can force it to take you bowling many times.')

I asked a source of mine who works at one of the casinos that utilize this technology. Besides the Treasure Island, this technology is also used at casinos in California, Michigan, and Mississippi. Here is what he said,

How To Play Slots Odds

'Nothing can be changed if there are credits on the game. The slot machine will always reject any changes sent when there are credits on the meter. In Nevada, the machine also has to be idle for four minutes prior to and following any changes. It’s also not completely transparent to anyone standing in front of the slot machine. A black window pops up that says ’Remote Configuration In Progress’ (or something like that).

We mainly use ours to change the available denominations on our games. Similar to how table games will raise minimum bets on when the casino is busier, we will remove lower denominations on Friday morning and return them on Monday morning.'

So, rest assured, that the slot manager can not tighten up a game on you just because he doesn’t like you. As long as you have credit in the game, nothing can be changed.

If you are implying the casino is changing the odds of the game while you're sitting there playing it, then I would say that is just a myth. To change the odds of a game, the slot maker would have to open up the game and change the EPROM chip. With server based game, where this can be done remotely, regulations require that the game be unplayed for a certain number of minutes before any changes can made.

If you are implying that the casino sets a slot machine loose for the first so many days, to draw new players, and then switches the EPROM to a stingier one, then I would disagree as well. That could easily be done, and legally, but I doubt it is. In my slot machine survey I found that any given casino was fairly consistent in how loose or tight they set their slots.

For the benefit of other readers, the way slot machines have usually work is that a chip inside the machine, called an EPROM chip, determines how loose or stingy the machine is. The vast majority of slots today still function this way. Contrary to popular myth, slots don’t achieve their desired return percentage by paying more when the actual return is too low and less when it is too high. Rather, it is just subtle changes in the reel stripping on video slots and the virtual weights on stepper slots. It is usually up to the casino manager which chip to put in. Some jurisdictions leave that decision up to the state. A common myth about these slots is that the slot manager can flip a switch in his office and cause any slot machine, or all of them, to pay more or less. The truth is a slot technician has to open up the machine and physically change the EPROM chips.

However, with the new generation of 'server-based slots,' the myth has potential to be a reality. Slots on this system can indeed be controlled remotely. The slot manager is now able to change the theoretical return, pay tables in video poker, denomination, as well as the entire game, in the comfort of his own office. Here in Nevada there are safeguards to prevent abuse of this power. The Gaming Control Board has the following regulation:

'The conventional gaming device or client station must be in the idle mode with no errors or tilts, no play and no credits on the machine for at least 4 minutes. After this time, the conventional gaming device or client station must be disabled and rendered unplayable for at least 4 minutes. During the time the machine is disabled a message must be displayed on a video screen or other appropriate display device notifying the patron that the game configuration has been changed.' — Technical Standards for Gaming Devices and On-line Slot Systems 1.140

Can Casinos Change The Odds On Slot Machines Real Money

So the slot manager couldn't tighten up the game you’re playing just because he didn't like your polka-dotted hat. However, in theory, he could loosen or tighten every machine that wasn’t being played. To finally get at your question, would he loosen and tighten the slots like a yo-yo depending on the time of day or day of the week? On my forum, I argued that would be bad business, but many who submitted comments disagreed with me. To help argue my side, I asked Nick Dillon, Executive Vice President/Assistant General Manager at the Barona Casino in San Diego County about it. Here is what he wrote back.

'The concern with SBG (server-based games) is that the manufacturers and most casinos are looking at it mostly from a cost savings (less slot techs/labor needed to convert games, etc) perspective. At Barona, we really only want it if it proves a true value to the player. We have approximately 80 units on the floor that we began testing a couple of years ago. We are not yet at the point where we can say there is a true benefit to the player. We have tested many aspects of these games but have never raised/lowered the hold based on time of day, day of week, etc. We have, however, tested some other things. One is changing the minimum denom based on day of week (penny during the week moved to nickel on the weekend, for example). The idea being the same as table games whereby the denom (table minimum bet) moves higher when demand is peaking. This maximizes revenue. However, we found that was not the case with our test (likely because tables are limited and full capacity during the increase, but slots generally are not, and because a “penny” player can actually be a “dollar” player regardless of what min denom he is playing). We found more dismay from guests that were used to finding their preferred game/denom and that it was now changed. We also tested changing only the default denom from penny to nickel. This is the denom that shows on screen when the game is idle. The majority of players may not be aware of multi-denom and play the default the majority of time. Again, we found no real difference in revenue.

As evidenced by our Loose Troop and Manufacturers Best programs, best blackjack rules, loosest video poker, no ATM fees, etc. we truly believe the player deserves the best gamble he can get. We feel that providing the longest play time for the dollar is the best strategy we can employ. There is no need to play with hold percentages and adjusting them 1-3 points either way for a day or two. Of course, a Strip property may feel differently as they only have a limited amount of time to win the money.

We are hopeful that we can help push the manufacturers to continue to develop SBG in favor of the player. We are hopeful that a player can put his player card in and his preferred games, denoms, etc will appear for his enjoyment at whatever device he sits. There are so many opportunities for this to be a great product for the player, which we believe will be good for our casino and the industry. If cost savings also come, great, but that should not be the main focus of a product like this.' -- Nick Dillon

In conclusion, I think you are safe playing server-based slots. If you don’t believe me, keep an eye on the video poker pay tables. If you don’t see those going up and down on a daily basis, chances are the slot returns are being left alone as well.

Slot Machines Odds Of Winning

This question was raised and discussed in the forum of my companion site Wizard of Vegas.