How Slot Machines Work – RNG, RTP and Volatility

The first slot machines were invented over one hundred years ago, long before computers came along. They were mechanical devices featuring an array of drums. On the drums were various symbols. When a lever was pulled, the drums spun around, coming to a random stop. If the symbols matched up, you won. If not, you lost. Figuring out your odds of winning the big prize was as simple as multiplying the number of symbols on each drum together. Not anymore…

Since the dawn of computer technology, these games have been programmed to defy traditional odds. There are no drums. The number of symbols per reel is not static. Everything is controlled by a computer chip running a software program, designed to pay out a very specific percentage of its take.

The three main programmable functions of a slot machine are the random number generator (RNG), the return to player (RTP), and the volatility. Let’s take a closer look…

Random Number Generator (RNG)

Remember the movie, The Matrix, when the green numbers kept raining down the computer screen? That’s an RNG. It’s a random strain of seemingly endless numbers generated by a computer. The algorithm it generates determines an outcome. There are countless applications for an RNG in the real world, but few so famous as casinos games.

In a slot machine, the RNG determines exactly what symbols will land in each position on the reels. If you could see the RNG, you would never be able to read it. Each and every number in the sequence is changing with each passing nanosecond. It does not stop until the exact moment a player presses the SPIN button. At that very moment, the sequence of symbols is determined by the number produced. As a player, we still see the reels spinning as they come to a slow halt, but the machine already knows where they are going to land, because the RNG told it so.

The whole purpose of the RNG is to ensure no one – not the players, the casino managers, or the players – is able to predict what will happen on any given spin. It’s all about timing. Press at just the right moment, and the jackpot is awarded. For this reason, a machine could pay back-to-back jackpots just as easily as withholding the jackpot for more than a year.

Knowing that this is how a game works, it’s hard to imagine that anyone could know how to predict when a slot machine will win. And yet, so many seem capable of doing so. More on that in a moment…

Return to Player (RTP)

The RTP is the amount of money a machine pays out, compared to what it takes in. The RTP is always displayed as a percentage. For those of you familiar with how “house edge” works, the RTP is the opposite of the house edge. RTP refers to the amount players win back, whereas house edge is the amount the casino wins. Put them together, and you get a total 100%.

For example, let’s say a slot machine has a 95% RTP. This means the game will pay back 95% of its monetary intake over time. The other 5% is the amount the casino wins. Theoretically, if you were to spin the reels 100 times on this machine at $1 per spin, you would end up with $95 left. The important word here, however, is “theoretically”.

RTP is always theoretical. Yes, the machine will meet its RTP. It’s a computer. They don’t make mistakes. But the RTP will only be met over a very long period of time. We’re talking 20-25 years. So no, you’re not going to win exactly $95 back and lose $5 for every $100 you wager. If that were the case, every player would lose and no one would ever want to come back to the casino. That’s where volatility comes in…

Volatility

A game’s volatility determines how often it is likely to strike a winning combination, and the average size of each prize paid. It can be low, medium, or high. A low volatility game is one that pays out very small amounts very often. A high volatility game will pay high prizes, but not very frequently. And a medium volatility is a balanced game, where mid-sized payouts occur on a regular, but not too regular, basis.

The volatility of a machine will not alter its RTP. Over time, they all perform equally. But in the short term, their attributes can seem very different. At low volatility, a machine will arrive at its intended RTP more frequently, whereas a high volatility game will have much greater upswings and downswings.

• Low Volatility = Lower Risk, Lower Chance of a Big Payout

• High Volatility = Higher Risk, Higher Chance of Big Payout

How to Tell if a Slot Machine is Due to Win

If a game has not paid out a decent sized win in a relatively long period of time, it is said to be “due” to hit. When a progressive jackpot reaches record height, more people play it because they feel it’s due to strike any moment. This certainly seems like a logical mode of action. The game will pay out big at some point, and the longer it’s been since the last big payout, the closer that moment has to be. But is it really possible to predict exactly when it will happen?

As we’ve already learned, a slot machine’s RNG makes it impossible to know the exact moment a game will pay out a jackpot. But knowing when a relatively large payout is due – that’s really not so far-fetched.

We know that game’s are destined to meet their RTP. And we know that an RNG determines every outcome the moment the SPIN button is pressed. Wouldn’t it make sense that the likelihood of the RNG producing a winning combination of numbers would be amplified by an actual RTP that is far below its intended RTP?

The real problem with this theory is that you have to know what a game’s actual RTP is, compared to its intended RTP. The only way to know if a game is far enough behind to potentially impact the value of the RNG algorithm is to sit back and watch the game for a long period of time. If you have the patience for it, give it a shot.

Does this Slot Machine Have a Temperature Gauge?

Some say slot machines can be hot or cold. Some believe this is a metaphorical statement, while others swear that game’s can produce a genuine thermal output. We’ll start wit the metaphorical…

A slot machine is hot when it is producing above average wins. It could be paying more frequently than its volatility implies, or it might be paying larger prizes than average. There are slots enthusiasts out there that will only play hot slot machines, hoping to ride that wave of success all the way to shore. Then there are players who avoid these game’s for fear they’ve paid all they’re going to pay for a good long while.

The opposite is true of a “cold” slot machine. A cold machine is one that is paying well below average. As we’ve already discussed, a game that hasn’t paid out a decent prize in a long time gets labeled “due” for a win. Contrary to hot-slot-lovers, some players will lie in wait for a slot machine to become very cold, then pounce on it as soon as the previous player leaves, expecting a quick strike.

As for those who believe a machine can become physically and detectable hot or cold, I’ve never experienced this myself. Maybe it takes a special kind of person – someone with a sixth sense, or one who can sees auras. Those who attest to its accuracy say a hot machine is ready to pay, and a cold one is not. My suggestion would be to walk the aisles and, if you feel a warm spot, give it a try.

The Correlation Between Slot Variance & Luck

A slot machine’s variance is how far it strays from its RTP. It is similar to volatility, except that volatility defines how much it should stray, whereas variance defines how much its actually straying at any given time. Variance is, in reality, what the majority of gamblers refer to as “luck”.

When a player is having a good day at the casino, we say he is very lucky. One who is having a bad day is said to be unlucky. Luck is either on your side, or it’s not. As fun-loving gamblers, we attribute a lot to luck, or a lack thereof. But variance is the technically appropriate term.

It is variance that allows some casino players to win large amounts of money, without hurting the casino’s bottom line. Those who win are on the receiving end of a game’s variance (lucky). But many more players lose, or fall on the negative side of that variance (unlucky). If one player wins a $10k jackpot, imagine how many players have to lose to pay for it, and still ensure the casino gets its due.

Suffice it to say, for all those who get lucky, many more will be unlucky. It is those who genuinely believe that you make your own luck that tend to proscribe to the theory that you can tell when a slot machine is about to win. Which brings us to our final segment…

Five Ways to Better Your Chances of Winning on Slots

After all you’ve read, do you think you know how to tell if a slot machine is going to hit? Whether you answered yes or no to that question, here is some genuine strategic advice that really will give you the best odds of leaving the casino a winner.

1. Higher RTP is Better

Look for slot machines with the highest RTP. It doesn’t mean you’re going to win, but it does increase the potential for winning. Not all games will display their RTP, but most will define it near the end of the paytable’s Info section.

2. Play Online Slots

Land-based casino slots have a typical RTP range of 85%-95%. Online slot machines have much higher RTPs, often ranging from 95%-97%. Online slots are also more likely to reveal their RTPs in the Info section.

3. Utilize Free Spins

Take full advantage of free spins bonuses whenever possible. These promotions come with wagering requirements and other stipulations that must be met before you can cash out any winnings, but it’s hard to complain when those spins aren’t coming out of your pocket book.

4. Beware Branded Titles

As a society, we are drawn to things we are familiar with. If we like something, we flock to its brand mimicry. Case in point – The Ellen DeGeneres Show. It is immensely popular. If you love Ellen and her show, and you walk into a casino and see her face plastered on a slot machine of the same name, odds are you’ll want to play that game. Casinos and slot manufacturers know this, and use it to their advantage, which is why branded slots tend to have the lowest RTPs. Steer clear.

5. Ask the Locals

Local slots players who frequent a casino know exactly which games pay out best, and which ones do not. So long as you’re not infringing on their seats, they are usually happy to share that information. In fact, there are social media groups dedicated to this topic. All you have to do is ask.