The two slots machines operate differently. The Class II slot machines are common in slots parlors. They are attached to Native American Casinos or horse racing tracks. Owing to improved tech tools, Class II slot machines have become more sophisticated. So much so that casual punters have a hard time telling them apart from Class III slot machines. The RTP (or Return to Player) is a number that indicates your odds of winning at a slot machine. The number connected to the RTP shows the percentage of total wins, over the total stakes played. The RTP is expressed on a scale from 1 to 100, with 100 being your best option (a very loose slot) and 1 being the RTP of a slot you will nearly never. Your odds of winning are better than this, as you can hit five bells, five whistles or five of any other set of symbols, so on this machine your odds of any set of five are actually 5 x 0.032%, or 0.16%. So once in every 625 spins of this hypothetical machine, you’ll hit your set of five identical symbols for the jackpot. Megabucks progressive slots generally have the worst win percentage because the huge jackpot outweighs the bad odds. The best win percentages came from high-roller slots. Slots that accept denominations of $5, $25, and $100 returned 94.05%, 94.97%, and 94.35%, respectively.

• Odds Of Winning Slot Machines
• How To Win On Slot Machines Tips
• Odds Of Winning Slot Machines

• Appendices
• Slots Analysis
• Miscellaneous

Introduction

When it comes to gambling, the easier a game is to understand the worse the odds usually are. This is certainly the case with slot machines. Playing them is as easy as pressing a button. However, between the high house edge and fast rate of play, there is no quicker way to lose your money in a casino.

Before going further, let me make clear that this page addresses the way slot machines work in most parts of the United States and the world. However, some parts of this page do not apply everywhere. For example, I state that slot machines have a memory-less property, where the odds of every spin are the same. In some places, like the UK, some machines in bars, called 'fruit machines,' have a mechanism that guarantees a certain profit over the short run, which causes the game to go through loose and tight cycles. These games do not have the usual independence property of the major slot makers.

How They Work

Whether you're playing a 3-reel single-line game or a 5-reel 25-line game, the outcome of every bet is ultimately determined by random numbers. The game will choose one random number for each reel, map that number onto a position on the reel, stop the reel in the appointed place, and score whatever the outcome is. In other words, the outcome is predestined the moment you press the button; the rest is just for show. There are no hot and cold cycles; your odds are the same for every spin on a given machine.

Slot machines are just about the only game in the casino where the odds are not quantifiable. In other words, the player doesn't know how the game was designed, so it is difficult to look at an actual game to use as an example. So, to help explain how they work, I created the Atkins Diet slot machine (link). It is a simple, five-reel game with a free spin bonus round, much like IGT's Cleopatra game.

For information on how it works and all the odds, please visit my Atkins Diet par sheet.

For a more complicated example, featuring sticky wilds in the bonus, please try my Vamos a Las Vegas slot machine.

For information on how it works and all the odds, please visit my Vamos a Las Vegas par sheet (PDF).

Odds

The following table shows the casino win for Clark County Nevada (where Las Vegas is) for all slots for calendar year 2012. They define 'slot' as any electronic game, including video poker and video keno. I've found video keno to be about equally as tight as reeled slots, but video poker has a much higher return. So, the return for reeled slots should be higher than these figures.

Clark County Slot Win 2012

Source: Nevada Gaming Control Board, Gaming Revenue Report for December 2012 (PDF, see page 6).

Most players play penny video slots. Based on past research, I find the house edge on those to usually be set from 6% to 15%. In general, the nicer the casino, the tighter the slots.

Advice

While there is no skill to playing slots, there is some skill in selecting which machine to play and ways you can maximize your return. What follows is my advice, if you must play slots at all.

• Always use a player card. Slots may be a lousy bet, but the casinos treat slot players very well. A $1 slot player will probably get comped better than a $100 blackjack player. Of course, don't play for the reason of getting comps. You'll give them a lot more than they'll give you.
• The simpler the game, the better the odds. The fancy games with big signs and video screens tend to not pay as well as the simple games. However, slot players always tell me the fancy games are more fun.
• The higher the denomination, the better the odds. For that reason, it is better to play one coin per line on a 5-cent game than five coins per line on a 1-cent game.
• Don't forget to cash out and take your ticket when you leave. It is easy to forget after hitting a jackpot.
• Try to play slowly and as little as possible to get your fix.
• In some games there is a skill feature, like Top Dollar. In such games, advice is usually offered, which you should take.

Myths and Facts

Just about everything that players believe about slots is untrue. Here are the most common myths and facts. As a reminder, this page is based on slot machines commonly found in the United States. Some machines, like 'fruit machines' found in the United Kingdom work differently.

• Myth: Slot machines are programmed to go through a cycle of payoffs. Although the cycle can span thousands of spins, once it reaches the end the outcomes will repeat themselves in exactly the same order as the last cycle.

  Fact: This is not true at all. Every spin is random and independent of all past spins.

• Myth: Slot machines are programmed to pay off a particular percentage of money bet. Thus, after a jackpot is hit the machine will tighten up to get back in balance. On the other hand, when a jackpot has not been hit for a long time it is overdue and more likely to hit.

  Fact: As just mentioned, each spin is independent of all past spins. That means that for a given machine game, the odds are always the same. It makes no difference when the last jackpot was hit or how much the game paid out in the last hour, day, week, or any period of time.

• Myth: Machines pay more if a player card is not used.

  Fact: The mechanism that determines the outcome of each play does not consider whether a card is used or not. The odds are the same with or without one.

• Myth: Using a player card enables the casino to report my winnings to the IRS.

  Fact: That makes no difference. If you win $1,200 or more they will report it either way. If you have a net losing year, which you probably will, at least the casino will have evidence of it. Such annual win/loss statements may be used as evidence to declare offsetting loses to jackpot wins.

• Myth: The slot department can tighten my game with the press of a button remotely. Thus, you better be nice to the staff and tip them well, or they will use a remote control to have the machine take you down in a hurry.

  Fact: There is now some truth to the myth that the odds of a machine can be changed remotely. Such 'server-based slots' are still experimental and in a minority. Even with server-based slots, there are regulations in place to protect the player from the perceived abuses that could accompany them. For example, in Nevada a machine can not be altered remotely unless it has been idle for at least four minutes. Even then, the game will display a notice that it is being serviced during such changes. (source) Meanwhile, for the vast majority of slots, somebody would physically need to open the machine and change a computer chip, known as an EPROM chip, to make any changes.

• Myth: The machines by the doors and heavy traffic flow areas tend to be loose while those hidden in quiet corners tend to be tight.

  Fact: I've studied the relationship between slot placement and return and found no correlation. Every slot director I've asked about this laughs it off as just another player myth.

• Myth: Slots tend to be looser during slow hours on slow days of the week. However, when the casino is busy they tighten them up.

  Fact: Nobody would take the trouble to do this, even if he could. The fact of the matter is the casinos are trying to find a good balance between winning some money while letting the player leave happy. That is best achieved by slots loose enough to give the player a sufficiently long 'time on device,' as they call it in the industry, with a reasonable chance of winning so he will return to the same casino next time. If the slots are too tight, the players will sense it and be unlikely to return.

  The kind of place you're likely to find tight slots are those with a captive audience, like the Las Vegas airport. So, if the slot manager feels that 92% is the right return for a penny game, for example, he is likely to set every penny game all that way, and keep them that way for years.

Play

Reviews

• Dazzle Me (NetEnt)
• Mr. Vegas (Betsoft)
• Sparks (NetEnt)

Internal Links

• Appendix 1 shows the details and analysis of almost 4000 actual spins on a Reno slot machine.
• Appendix 2 shows an example of the virtual reels behind a hypothetical slot machine and how the average return is calculated.
• Appendix 3A: 2003 Las Vegas slot machine rankings.
• Appendix 3B: 2002 Jean/Primm slot machine rankings.
• Appendix 3C: 2002 Tunica slot machine rankings.
• Appendix 3D: 2002 Henderson/Lake Mead slot machine rankings.
• Appendix 3E: 2002 Quarter and dollar returns for Las Vegas slots
• Appendix 4 shows how the return is calculated for my Wizard's Fruit Slot Machine.
• Appendix 5 analysis of the 21 Bell Slot Machine.
• Appendix 6 Analysis of Red, White, & Blue Slot Machine.
• Lock and Roll analysis of the skill-based slot machine found in North Carolina.
• Deconstructing Jackpot Party analysis of the video slot machine.
• Deconstructing Lion's Share analysis of the classic MGM progressive game.
• Deconstructing Cleopatra analysis of the popular IGT game.
• Deconstructing Lionfish analysis of the slot game found on many Game Maker machines.
• Deconstructing Megabucks.
• Deconstructing the Atkins Diet slot machine.
• Deconstructing Lucky Larry's Lobstermania.
• Deconstructing Hexbreaker.
• Deconstructing Blazing Sevens.
• Deconstructing Hot Roll.
• Mystery progressives on Ainsworth slots.
• Mystery progressives on WMS slots.
• Baltimore Sun article, in which I am quoted.
• 100% Rebate on Slot Losses Promotions: When to quit playing when all losses are refunded.

External Links

• For a simplified explanation of slots, please see my companion site Wizard of Vegas
• German translation of this page is available at richtigspielen.com
• Another decent overview of how slots work and some practical advice for playing them is How Slot Machines Work at VegasClick.com.
• PAR Sheets, probabilities, and slot machine play: Implications for problem and non-problem gambling by Kevin A. Harrigan and Mike Dixon, University of Waterloo, Waterloo, Ontario, Canada. This is an outstanding academic paper that details how some popular slot machines were designed.
• PAR Sheets, probabilities, and slot machine play: Implications for problem and non-problem gambling - Academic paper based on the par sheets for some modern slot machines

If you thought winning at online slots was about slamming the 'Spin' button, crossing your fingers, and hoping for the best, think again.

It's important to have even a basic understanding of the odds involved in slots if you're going to choose the right game and have a profitable slots life.

Today's video slots are hugely complicated and well-crafted beasts, and while that means they're safer than ever, it also means they're harder to predict.

Random Number Generators

Once upon a time, slot machines were mechanical behemoths powered by mechanisms that fixed the various combinations that the slot landed on.

Today's video slots, however, are powered by microprocessors (and programs in online slots) called Random Number Generators.

RNGs are formulae programmed into the games which generate random numbers (or arrangements of symbols) as the reels fall.

Any good online casino will have its RNGs audited by an independent body like eCOGRA or TST regularly for fairness. Software developers themselves are also audited before they can be given out gaming licences to operate.

Slot Par Sheets

Every new online slots has a 'par sheet', a blueprint for the payouts and permutations that goes into the game.

On a typical par sheet you'll find a list of the symbols featured on each reel and the quantity. The number of symbols on each reel varies wildly from one slot to another, and that's what can affect the payouts.

Where one game has 30 symbols on a reel, for example, another may have over 200; that can result in many more thousands of possible winning (or losing) combinations.

Par sheets will also list jackpot totals and how many spins are typically needed to hit a jackpot. Remember, though, this doesn't mean a slot is fixed; the reels still spin at random and independently of each other.

Payouts and Combinations

Odds Of Winning Slot Machines

While it's not necessary to calculate every odds in a slot, it's a good idea to have a rough idea of how often a three-symbol combination hits.

The chance of you hitting a winner is related to the amount of reels in the slot and the number of icons on each of the reels.

Let's take a classic 3-reel slot. With three reels, and 20 symbols on each reel, the odds of hitting one exact symbol is 20/1, or 1 in 20. If it's 20/1 to hit one symbol, then it's 20x20x20 = 1 in 8,000 to hit a combination of three symbols; or, there are 8,000 possible combos.

Now let's say you're looking to hit a jackpot with special bonus symbols. There's just one of those on each reel, so the chance of hitting the jackpot is 1/8,000. If you have four jackpot symbols on each reel, your chances of hitting a winning combo drastically lower to 4/20 x 4/20 x 4/20 = 12 / 8,000 = 1 in 666.

But most online slots have five reels, which puts the possible combinations into the millions.

Understanding RTP (Return to Player Percentages)

Every slot is designed to pay back a certain percentage of bets to players over the long term. These Return to Player Percentages (RTP%) vary from game to game, and are theoretical. In addition, the RTPs are usually calculated over a very long-term period of betting.

Remember that slots spins are random, but odds are programmed into slots depending on the number and layout of symbols on the reels.

How To Win On Slot Machines Tips

Many online casinos and developers list their RTPs. You'll even find them tucked away in the slot Paytable. Online slots tend to have better RTPs than their land-based cousins (ranging from 85% in a live casino to up to 97% in an online casino), and it's a good idea to get used to which slots offer the best long-term payouts.

Volatility in Slots

Odds Of Winning Slot Machines

You'll sometimes hear slots referred to by their volatility.

Essentially, high-volatility or volatile slots carry a higher risk to your bankroll. You might go a long period without winning a penny, then hit a big jackpot.

On the reverse, low-volatility slots offer plenty of frequent, smaller wins. You might not hit a big jackpot as with a volatile slot, but they're better on your wallet - and your heart!

For action junkies looking for the big win, high-volatility slots offer lots of action but you'll need to weather the variance (swings in bad and good luck).

For an easy way to work out if a slot is volatile, head to the paytable. Every slot has one that lists the various payouts and jackpots. If there seems to be a lot of mega jackpots in the game, it's probably high-volatility.

Volatility is a personal preference at the end of the day. If you can handle the barren periods but want to hit that once-in-a-hundred-spins jackpot, choose a high-volatility slot. If you prefer a small win every couple of spins, a low-volatility game is for you.

Find the Best UK Slots On The Net

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At VegasSlots.co.uk, we offer UK players hundreds of free-play slots so you can test out the games, check the RTPs and see if that bonus feature really is as random as it seems.

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