All about Slot Machines

How they work, Common myths, and Strategies

by Michael Bluejay | ©2002-08

I don't usually mention my credentials in an article but there is so much misinformation about slots on the net you may want some help in figuring who's blowing smoke and who is the real deal. So here's what I can tell you:

• I helped the legendary Wizard of Odds with some of his groundbreaking research into slot machines (in fact, that's how we met).
• I had a cover story in Casino Player magazine.
• There are several casinos in Nevada I'm not allowed to play at because of my skill. (Not at slots, because no one can beat slots in any meaningful way.)
• I'm very familiar with the probability and math behind the programming that I can design a machine and walk you through calculating the specific payback.
• I put my money where my mouth is. For years I've had a $1000 challenge posted on this page for all the so-called experts who supposedly have some winning slot system, or who believe that the casinos put their looser slots in certain areas. The number of other "experts" who have taken me up on this? Zero.

With that out of the way, let's talk slots.

In the 1980's slot machines surpassed table games like craps and blackjack as the most popular game in the casino. Slots and video poker now account for more than 70% of the casino's total take. Why the surge in popularity? Simple: Bigger jackpots. With computerized virtual reels it's harder to hit the top jackpot, and since the jackpot will be hit less frequently the casino can make the jackpot amount larger.

This is true even with machines that look mechanical and have physical spinning reels. It's just an illusion. The whole game is controlled by a computer, using virtual reels. These days there are no more purely mechanical slots. We'll talk more about how the computer controls the reels in a minute.

Play this slot machine with fake money or real money at Bodog No popups, no download, no registration, no B.S., just the game. One click and you're in.

Slots offer the ability to win a lot of money for a small bet. If you put $5 on a blackjack table the most you can win is $7.50. But $3 in a slot machine could net you thousands or millions.

Still, there are three big problems with playing slot machines vs. other casino games. First, the casinos usually don't disclose the odds on individual machines, so you can't really be an informed player. Second, whatever those undisclosed odds are, they're usually bad -- far worse than table games like craps, baccarat, and blackjack. And finally, slot machines are usually played much faster than table games, so they suck away your money even quicker.

I therefore recommend that you don't play slots very much, if at all. You might counter that with, "Yes, but if I expect to lose, and figure that that's just the cost of the entertainment, then what's wrong with that?" Nothing, except that if you played at table games instead you could play for a lot longer, have more fun since you're playing with other human beings, and have a much better chance of walking away a winner. And isn't winning the most fun of all?

Maybe you play slots because you want the chance of a big jackpot, which you thought you couldn't get with table games. But you can! Many table games have an optional side bet which gives you a shot at a big jackpot, and you can also use a progression betting system to try to win thousands or millions at a table game -- with a lot better chance of success than winning the same amount of money at slots.

I hope you'll consider playing table games instead of slots, and I have a crash course in table games to help you do that.

If you must play slot machines, set a limit before you start playing of how much you're willing to lose, and then stop once you lose it.

Since I know many people will play slots anyway, here are some tips to help you lose the least amount of money, and to help you understand the games better in general. If you work hard for your money, you might as well keep as much of it as you can. By the way, these are better tips then you'll find just about anywhere else (until everyone starts illegally copying this website, that is).

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Strategies for Saving Money

Play the lowest denomination machine you're comfortable with.

Even though lower-stakes machines have worse odds, you'll still lose less money on them. A 90% 5-coin nickel machine loses $18.75/hr. on average, while a 98% 2-coin dollar machine loses $30/hr. (The disparity in payouts between different denominations usually isn't that extreme, but I'm just showing that even when the difference is extreme you'll still lose less money by playing the lower denomination machines.)

Play machines which are advertised as paying back a specific high percentage.

Most casinos won't tell you how much their slots pay back, but some do. On the Vegas Strip, Stratosphere and Riviera have 98% dollar slots, and Circus Circus has 97.4% dollar slots. Fitzgeralds in Reno has a section of about 50 dollar slots whose average payback is 97.4%. If you're playing dollar slots, I recommend that you play only at these casinos, or other casinos which advertise a specific high payback.

Ignore claims such as "Loosest Slots" or "High Payback". Those terms are meaningless since they're not specific. Also ignore specific numbers married to vagueness, such as "up to 98% return" if the casino doesn't tell you specifically which machines are 98%.

Limit play on progressives.

Progressives are the machines with the LED marquees that show the ever-increasing jackpots. They typically pay back 2-7% less than standard machines, so you should play them sparingly, if at all. If you must play (because you want a shot at a huge jackpot), play a two-coin machine instead of a three-coin machine, and look for a $0.05 or $0.25 machine instead of a $1.00 machine.

Avoid video reels.

Video reel slots often pay back a percentage point or two less than their mechanical counterparts. Also, the ability to play five coins on each of nine lines ($1.45/spin) could seduce you into betting a lot more than you should.

Use a slot card.

Get a slot card and use it at any casino you play at. While the cashback rewards for slot points are usually insignificant, playing on a slot card means that the casino may give you free meals and will usually mail you offers for free or deeply discounted rooms, and that can save you a bit of money.

Contrary to popular myth, using a slot card has zero effect on whether you win. I won several jackpots at Fitzgeralds in Reno with my slot card in. (I was playing only because they were running a special promotion which improved the odds of winning. Normally I don't play slots because I can get better odds at table games.)

Learn other games.

Since you'll likely be bored by playing nothing but slots (especially if you're losing, and you probably will be), learn a table game so you can play it when you want to take a break from slots. Over time you may play the tables more and the slots less, especially since you have a better chance of winning at the tables, and because it's more fun to play with other people. Check out how your expected loss for playing 10 hours of slots vs. table games:

Game	Est. Loss for 10 hours play
Slots, $1.00 (2-coin game)	$800
Slots, $0.25 (3-coin game)	$360
Mini Baccarat, $5/h.	$80
Roulette, $5/spin	$79
Blackjack, $5/hand	$25
Craps, $10/round ($5 Pass, $5 odds)	$25

Assumptions: Slots played 800 spins/hr. Slot returns are average for Las Vegas Strip & Downtown casinos as published in Jan. 2002 Casino Player (94% for quarters and 95% for dollars). Mini Baccarat, Roulette, Blackjack, and Craps played at 30, 150, 100, and 30 rounds/hr. respectively. Table games played as per crash course strategies listed below. Table shows mathematical expected result, though results obviously will vary due to short-term fluctuation.

If this piques your interest, check out our crash course on table games.

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How do Slot Machines Work?

This part of the article got so big I moved it to a separate page on how slot machines work.

Slot Returns and Paybacks

The terms returns and payback are often used interchangeably but in this article I'll assign specific meanings to avoid confusion.

The return of a slot machine is the percentage of money paid out vs. the amount of money paid in. If you put $100 into a machine and get $92 back, your return was 92%. Many online casinos hire accounting firms to verify their returns in order to prove to customers that they're honest. The reports that these firms prepare show the return of the various games. If all players put $1,000,000 into a casino's machines in one month, and they collectively won $967,000, then the return was 96.7%. The 3.3% that wasn't paid out is the casino's profit, in this case $33,000.

Of course your actual return is going to vary at every session, even on the same machine. If you knew exactly what the outcome would be then slots wouldn't be any fun and no one would play.

The return is contrasted with the payback, which is the theoretical amount the machine would pay back over an infinite number of spins, according to the math. If a machine is set to pay back 95% then if it were played forever it would return 95 cents on the dollar for every dollar played.

But of course you can't play forever. In the short term anything can happen, and that's why people play slots. Obviously if you put a dollar coin into a machine you're either going to lose that whole dollar or win some random number of coins, and in no event will the machine spit back exactly 95 cents at you. But if you sat there and played for years, your wins would equal about 95% of what you put into the machine. What we know is that the longer we play, the more likely our return will equal the theoretical payback.

When a casino orders a slot machine from the manufacturer, it specifies the payback it wants for that machine, which generally ranges from 90-98%.

That may seem like a good deal, but it's not. If you're getting back 95% of your money, that means the casino is keeping 5%. If you play a dollar machine, two coins at a time, 800 spins an hour, for one hour, you're putting $1600 into the machine. The casino's 5% take means you lose $80/hr. on average. Ouch.

This is one reason that casinos don't cheat with slot machines: They don't have to. The odds are so overwhelmingly bad, all they have to do is put the machine on the floor and rake in the money.

Understand that your expected loss is based on how much money you play, not how much money you take with you. For example, you might think, "Okay, I'm bringing $500, and the slots take an average of 5%, so I should lose about $25." Not even. You'll go through that $500 in less than an hour on a $1, two-coin slot, and lose an average of $25 on that. But then when you play the $475 or so that you got out of the machine, you'll expect to lose 5% of that, etc. Losing a bit every time you replay your bankroll is called the grind. The casino grinds you down. It doesn't matter whether your return is 90% or 99%, if you play long enough at any game you'll eventually lose all your money. To figure your expected loss, figure how much you're playing total. Here's our primer on figuring expected loss.

The return on a machine is figured by the manufacturer, by taking all possible combinations and adding how much would be won on those combinations. For example, if a machine is picking a number from 1 to 64 on each of three reels, then there are 64³ = 262,144 combinations. Let's say they have a computer play out all these combinations at the two-coin per spin maximum, which would represent 524,288 coins wagered, and they find that 498,074 would have been won. So 498,074 / 524,288 = 95%. Ta-da. Here's a more detailed analysis of how the payback on a machine is calculated.

In general, the higher denomination the machine, the higher the payback. For example, the average payback between Vegas Strip & Downtown casinos is 95% for dollars but only 94% for quarters and only 92% for nickels. But even though the odds are better on the higher-stakes machines, you'll still lose more money playing them, because you're wagering more money. If you want to limit your losses, play the lowest stakes machines you're comfortable with.

Who has the best slot paybacks

It's usually not easy to find out the payback on a particular machine, because casinos don't like to tell you. Exceptions, as noted earlier, include Fitzgeralds, Stratosphere, and Riviera in Vegas, all of which advertise a 98% payback on specific slots.

Non-Indian casinos are required to file reports on their slot returns to the government, and since this is public information, Casino Player magazine publishes the results every month. Unfortunately, this isn't ideal for a number of reasons. (1) While you can see the returns for individual casinos like Tropicana and Showboat in Atlantic City, the Nevada returns lump all the casinos in an area together. (2) The returns listed are actual returns for one month, and an unusual number of jackpots (or lack thereof) can skew the results. (3) Video poker machines are mixed in with the slots, so you can't see how much is from slots and how much is from video poker. (4) Most Native American casinos don't have to report their returns, so they don't.

What's most useful about the return tables is seeing what geographic regions have the best slot payouts. For example, Atlantic City, surprisingly, seems to have some of the worst slot returns in the whole country. Nevada has the best, and within Nevada, the best returns are usually in North Las Vegas and Reno, followed next by Downtown Vegas. Not surprisingly, the Vegas Strip has the worst returns in Nevada, but even so, they're still way better than most of the rest of the country. As high as Vegas slot returns are, though, you'll still lose less money on average by playing blackjack, craps, or baccarat at $5/hand. Heck, with proper strategy you'll less at blackjack at $25 a hand than you will on a five-coin nickel machine with a 94% return. (If this gets your interest, see our crash course on table games.)

Number of Coins Played

Slots accept multiple coins per spin -- 2, 3, or 5 coins on mechanical slots, and 45 or more on video reels. When you win, your payout is matched to the number of coins you played. For example, three single bars may pay out $10 for one coin played, $20 for two coins played, and $30 for 3 coins played. Most machines have a bonus for the top jackpot. For example, 1 coin pays $1000, two coins pay $2000, but three coins pays $5000 (not $3000). This is to try to get you to play more coins at a time, since the casino makes more money that way.

Most gambling experts tell you to always play maximum coin, and if you can't afford to play maximum coin, move down to the next denomination (playing quarters instead of dollars, for example). These "experts" are wrong. The penalty for playing maximum vs. one coin is usually less than 1% of the total return, while the penalty for downgrading to a lower denomination slot is usually more than 1%. So you'll usually enjoy a better return (and have a better chance of winning) by continuing to play your high-stakes machine for one coin at a time rather than downgrading. Besides, the difference in return only becomes an issue if you hit the jackpot, and how often does that happen? (On typical slots, you can expect it to happen about once a month with full-time play.)

The advice to downgrade is good for a different reason, though: You'll be putting less money into the machines, so your expected loss will be smaller. You'll lose less on lower stakes machines even though the odds are worse, because you're not pouring as much money into them.

The above advice is geared towards typical slots. If you're playing progressive machines where the top jackpot is huge and keeps escalating higher (like Wheel of Fortune and Megabucks), then obviously you'd want to play the maximum coins, since the only reason to play progressives is for the shot at hitting the big jackpot. But limit your play on progressives, because the house take is often twice what it would be on a regular slot.

Strategy for Hitting the Jackpot

Since every spin is random, the most important way to increase your odds of hitting the jackpot are to pick a machine with the best chances of doing so. Since the casinos don't tell you what the odds are that makes your job difficult. In general, you know that the bigger the jackpot, the worse the odds. The odds are about 262,144 to 1 on a typical machine with a $10,000 jackpot. On Megabucks, with its multi-million dollar jackpots, the odds are closer to 1 in 50 million. Here are the odds of hitting the top jackpot on the progressive slot machines at Casino.net, along with the jackpot amount for the $0.25 and $1.00 machines on Dec. 17, 2003.

Based on these figures, Jack in the Box is clearly the best bet. The chances of hitting the jackpot are better than with Aladdin's Lamp and Haunted House, and the jackpot is larger than Gold Pirates.

It's significant that Casino.net makes their jackpot odds public. I've never seen another land or Internet casino that's up front with their players like this. Casino.net gets big, big kudos for making these figures public.

It doesn't matter how long it's been since the machine hit its last jackpot. If the odds of hitting a jackpot on one spin are 1 in 250,000, then they're always 1 in 250,000, whether the last jackpot hit last year or five minutes ago. No slot machine is ever "due" to hit. That's the way probability works. The odds of getting heads on a coin flip are always 1 in 2, no matter what you got on previous flips. If you just flipped ten heads in a row, then you're just as likely to get heads yet again as you are to get tails. If you're not convinced about this then see our article about exposing the gambler's fallacy. The point is, past events have no effect on future events. Many people would avoid playing a machine that just hit a jackpot because they think another jackpot is magically less likely, but in fact the odds are the same on every spin, no matter what happened before.

Irrelevant Stuff

The outcome is NOT affected by:

• How long it's been since the last jackpot.
• Pressing the button vs. pulling the lever, or vice-versa.
• Whether your slot card is inserted.
• The day of the week or time of day. (Casinos don't constantly change returns.)
• Whether there's a convention in town. (See previous.)
• Whether the coins are hot.
• Anything else you could think of. The RNG selects the combination, and THAT'S IT!

One casino patron asserted to me that a bank of machines was all "on the same circuit" and that if you got some friends to play them all simultaneously, you'd win. This has got to be the stupidest thing I've ever heard. What does it even mean, that the machines are "on the same circuit"? The same electrical circuit? Big deal. If I put all the lamps in my house on the same circuit and turn them on simultaneously I'm not going to win money or summon the Tooth Fairy. The RNG selects the symbols, same as always.

Where the highest paying slot machines are located

Frank Scoblete's 1994 book Break the One-Armed Bandits said that casinos place higher-playing slots in certain places, such as the ends of the aisles instead of in the middle. He based this on an interview with a casino slot machine manager. That might have been true at the particular casino Scoblete visited ten years ago (and it might not have been), but that's not the case today. Independent research by the Wizard of Odds confirmed that either all machines are set to the same payback level or placement is random. And a casino slot machine technician confirms that the casino doesn't put higher-paying slots in certain areas.

A cottage industry has sprung up reselling the information from Break the One-Armed Bandits. All over the Internet you can buy the "secrets" for finding out where the casinos put the higher-paying slots. But it's no secret, and it's not accurate anyway.

I have a challenge for any huckster claiming to know where the hot slot machines are in a casino:

I will meet anyone in Vegas to execute this challenge. Bring it on.

How to beat slot machines

You can't. There is no system or strategy that can overcome the house advantage on slots. The machine results are random, period. No casino is so stupid that they would put a game on the floor with a vulnerability that could be discovered. The casino feels safe only when they offer a game that has no secret to crack. If you were a casino manager, which of these would you do?

• Put machines on the floor that were truly random on every spin so that no player could ever get an edge over the casino, or...
• Put machines on the floor that had some sort of discoverable pattern and hope and pray that the players never figured it out.

Anyone who thinks that it's possible to find any sort of pattern in slot machine payouts is just wrong, plain and simple.

If a system could beat a slot machine and had been discovered and the first few people who knew about it started winning a lot of money, how long do you think it would take for the casino to notice and fix the problem? Is it plausible that the casino would willingly leave a game on the floor that they would lose money on hand over fist?

All this doesn't prevent people from selling systems that supposedly make you a slot winner. One of the more retarded of these is this one by "Insider Slot Secrets" which says you can "start making a minimum of $1,000 a day playing the slot machines". If it were true then why aren't they raking in $365,000 a year playing slots instead of having to resort to making $47 from selling their system? And how is it that all the people who have bought the system are each taking a third of a million dollars a year out of the casinos and the casinos aren't noticing, or going bankrupt?

I wrote to Insider Slot Secrets inviting them to participate in my $1000 challenge #2, below. They didn't even reply.

System sellers I have invited to participate in this challenge:

• Insider Slot Secrets (they didn't even reply)

I will meet anyone in Vegas to execute this challenge. Bring it on.

Misinformation from the Experts

It's easy to find slot machine myths and misinformation, even in published books, national magazines, and professional websites. We could spend forever providing examples of wrong info, but here are just some we've run across.

"There are plenty worse gambles [than slots] in the casino. Take a stroll down to the keno lounge or wheel of fortune, make some of the proposition bets at craps, make idiot plays at blackjack, bet a parlay at the sports book. An average loose machine pays better than roulette." --Slot-Machine-Games.net, Nov. 2004

It's disappointing to see this misinfo from this site because they do have some otherwise accurate info on their site.

While keno has a higher house edge than slots, slot machines definitely suck your money away faster. (SLOTS: 3-coin quarter machine x 6% edge x 800 spins/hr. = $36/hr. loss. KENO: $1 game x 28% edge x 7 games/hr. = $1.96/hr. loss.)

While an "average loose machine" may pay better than roulette how are you supposed to know which machines are loose? Most casinos don't disclose the odds on their slots. The average slot machine in general pays worse than roulette. And once you factor in that slots are played 25 times faster than roulette it's easy to see why you lose much slower at roulette than slots.

"[Casinos often] put their better-paying 'hot slots' in heavy-traffic, highly visible locations, with room for crowds to gather and cheer winners on. Such locations include crosswalks, elevated carousels, and banks of slots near the casino bar, lounges, change booth, and coffee shop." --Slot-Machine-Games.net, Nov. 2004

This isn't true, and not surprisingly, those making this claim never back it up. They certainly don't put their money where their mouths are. I've had an open challenge of $1000 to those who claim that location matters: They pick a "good" location for their machine and a "bad" location for mine, and after 1000 spins we see who's ahead. The number of "experts" who have accepted this challenge to date? Zero.

"The best odds in the casino are the dollar slot machines. After that, craps gives you the best chances of winning." -- The Travel Channel; I caught this one the Travel Channel in Aug. 2004. It's not an exact quote but it's pretty close.

They are way off the mark. Blackjack, craps, baccarat, single-zero roulette, video poker, and many other games give better odds than the typical dollar slot machine.

"Most slot machines are set to a 75% payback." -- The Travel Channel, as per above

It would be nice if these guys bothered to do a little research before misinforming millions of people. In fact, almost no slot machine is set that low. The typical range is around 88 to 97%. Even nickel video slots at McCarran Airport in Vegas pay in the mid-80's.

"You don't really have to know much to get into the game.... [B]e aware that nothing improves your odds of winning." -- Gambling Magazine

Not true. Selecting a high-return slot greatly improves your chances of winning, and most slot players fail to do this. That's why I recommend that slot players play only the high return slots at Fitzgeralds, Stratosphere, and Riviera in Vegas. Also, skipping the progressive slots in favor of traditional slots will improve your chances of winning.

"For many gamblers, the big decision isn't whether or not to play slots, but which slot to play. You'll be happy to learn that within certain limits, there is no right or wrong answer; it's just a question of what kind of machine serves your personal desires and style best." --Gambling Magazine

Wrong. See above answer.

"Most slot players don't realize how important the occasional jackpot is in holding down losses. A 94 percent-return machine isn't giving you back 94 cents out of every dollar. Mostly it's giving back less, because every once in a while, it gives you a bundle. If you aren't in position to win that bundle, your 94 percent machine might as well be a 74 percent machine." --Gambling Magazine

Whoa, you could tell these guys were guessing, huh? The jackpot never contributes as much as 20% to the return; it's more typically like 2%. If machines paid out only 74% between jackpots, nobody would play them.

"If you aren't playing max coins, you're gambling very poorly.  If the maximum number of coins seems too expensive (for example, $3 on a $1 slot), move to a lower denomination slot." --Gambling Magazine

"If you don't feel comfortable playing the maximum coins you should drop to a lower coinage. Play the quarters instead of dollars." --Gambling Magazine

"My advice is to fill the machine with the maximum amount of coins and play every available payline.  If you find yourself at a machine that is out of your budget then move on to a smaller denomination machine..." --Gambling Magazine

This common (and wrong) advice is addressed above. In short, the penalty for downgrading to a lower stakes slot is higher than the penalty for playing only one coin. You'll generally have a better chance of winning by playing only one coin on the higher stakes slot. On the other hand, it's a good idea to play lower stakes machines simply because you're wagering less and you'll likely lose less money, even though the odds are worse.

"Slots tend to pay off from 80 to 98 percent, meaning that for every $100 that somebody puts into the machine, the machine will pay back from $80 to $98." --Gambling Magazine

Probably the author knew what he meant, but just worded it poorly. The machine won't pay back $80 to $98 each time someone wagers $100, but rather will pay back $80 to $98 for all $100 insertions played on average over the long term (an infinite number of spins).

[Alludes to the highest return on a slot being 97%.] --Gambling Magazine

Fitzgeralds, Stratosphere, and Riviera in Vegas all have 98% slots. Fitzgeralds in Vegas and Reno actually have a couple that pay slightly over 100% (but of course, they're not telling you which ones).

"Ask an employee in the slots area which machine is the best to play (based on how often they have noticed people winning at it). Offer them a percentage of your profit for pointing you in the right direction." --Slot-Machine-Games.net, Nov. 2004

"Ask the staff. You have waitresses, coin attendants, and the machine attendants who do nothing but watch the slots all day. They will know best the machines that payoff more than others or which machines are due for a large jackpot." --Gambling Magazine

This is ridiculous. First of all, no machine is ever "due" for a jackpot; every spin is independent and completely random. Second, if employees knew of profitable situations in the casino, they wouldn't be working those low-paying jobs to begin with. Third, the volatility in a slot machine is so high that you can't get a feel for which machines pay out better even if you work with them day in and day out. The only way to find out is to play a lot and record your results. Even then, all you'd find is that the odds are so poor you'd be better off playing table games anyway.

Incidentally, a high-paying slot doesn't give the jackpot more frequently; it gives the small returns more frequently.

"The strategy calls for picking one Online Slot Machine. Spend an hour playing at different times during the day or night. You might find that some slot machines fall into a payout cycle and they tend to pay off around the same time every day or every couple of days. " -- TopSlotMachines.com

It doesn't matter when you play. There is no such thing as a payout cycle. The results are always random. Random, random, random -- that's how slot machines work.

Play Slots Online

Play this slot machine with fake money or real money at Bodog No popups, no download, no registration, no B.S., just the game. One click and you're in.

Again, I suggest you play something else rather than slots because the odds are so bad. Of course, if you play online with fake money then it doesn't matter. A good casino for free-play is Bodog, since it requires no download and no registration -- one click and you're in. You can play with real money too, though I hope you won't.

Other Resources (hand-picked)

• Wizard of Odds. Nobody knows more about the math of casino gambling than the Wizard. His survey of slot returns of Las Vegas casinos was groundbreaking and legendary.
• Slot Machine Fan. Useful, no-nonsense articles about playing slot machines, without the guesses and other B.S. so common on the net.

See also how to play:

• Baccarat
• Blackjack
• Craps
• Roulette
• Texas Holdem
• Video Poker