How Slot Machines Determine Wins and Values

How slot machines work to spin out wins and losses to players.

All slot machines are not created equal. This we know. The oldest games were built with mechanical drums, while the newest models are nothing more than big cabinets, with tiny computer chips and fancy LED screens. How they determines wins, losses, and the value of payouts, cannot possibly be the same. But it’s not just a matter of technological advancement that alters they way different machines get the job done. There are actually five different methods in which a slot can determine the results of any spin. We’ll talk about each of these, and how you can tell the difference before you sit down to play.

How Slot Machines Work – In The Old Days…

The oldest slot machines were built with mechanical drums, displaying symbols on physical reels. They were built with a special mechanism that ensured each reel would stop on a random position. This was the earliest form of what we know today as a “random number generator”, or RNG.

Manufacturers knew the probability of a slot machine landing on any possible outcome, because it was a matter of simple math. Multiply the number of reels by the number of symbols to get the number of possible combinations. Multiply the number of reels by the number of a specific symbol to get the number of ways that specific combination can appear. Divide the first result by the second, and you get the probability of that combination appearing. Easy, peasy!

When Computers Took Over – Circa 1980s

About 40 years ago, mechanical slots were replaced by computers. They looked and acted the same on the surface, but a programmed microchip did all the work. Still, it wasn’t much different than the old days. Class III, electronic slots (the ones found in casinos from Las Vegas to Atlantic City) are still powered by an RNG; albeit a more sophisticated one.

These newer slots use a computer program to rotate the numbers in a very, very long algorithm. Those spins are constantly changing, with each nano-second that passes, whether the game is actually being played or not. The moment the spin button is pressed, the RNG halts. The result of that long algorithm tells the machine what symbols to place in each position, with the pay table determining the payout (if any).

Bingo Games that Look Like Slot Machines

Tribal casinos all over North America are famous for their “Class II” slot machines. They look just like the Class III variety at other casinos, the way they spin out results is completely different. You see, most tribal casinos are not legally able to offer “gambling” games, but they can offer “bingo” and “pull tabs”. So, their Class II slots are actually bingo games disguised as slots.

Every time you spin the reels on a Class II slot (a.k.a. Bingo Liner), you’re actually buying a randomized ticket in a bingo game. Once enough slots (bingo) players press spin (buy a ticket), the game automatically draws numbers. If your bingo ticket wins, the slot machine spins out a winning combination equal to the value of the bingo ticket.

Many players never even know that this is happening, because their game just looks like a slot machine. Some are even named and designed to be identical to their most famous Class III cousins. But a bingo liner will always have one distinguishable difference. Somewhere on the screen, usually in a corner, you’ll see your bingo card displayed; winning numbers highlighting as the real game takes place in the background.

Video Lottery Terminals – Spin to Scratch-n-Win

Video lottery terminals, or VLTs as they’re more widely known, are not real slot machines, either. Much like those Class II bingo slots, VLTs are the equivalent of scratch-off lottery tickets. Lottery operators from all over North America – and especially here in Canada (Tap Tix, anyone?) – developed these games to offer slot machines in jurisdictions where gambling is illegal.

Here’s how they work. The computer is packed with pre-programmed, virtual scratch tickets. Each ticket is a winner or loser, with preset prize values on the winners. When you insert your money and spin the reels on a VLT, you are essentially putting your hand in a hat and drawing out one of those tickets. Once scratched, that ticket is removed from the batch. Spin again to draw another ticket. When all tickets in the batch are depleted, a new batch is uploaded.

In this way, the lottery operator is able to control exactly how much money it takes in, and how much it pays out.

Historic Horse Racing Slots – Too Complex to Care?

Whoever came up with this idea was either a genius or a madman. It is the most complicated of all “not rely a slot machine” mechanics. Historical horse racing (HHR) games are a lot like the bingo liner slots described above, except that players essentially get to choose their own card.

So here’s how slot machines work with the historic horse racing variable. Three actual horse races from the past are randomly selected by the machine. Each race contains 10 horses, meaning there are 30 possible horses to choose from. Each race has a win, place and show, so there are 9 possible horses that can win prizes of varying amounts. As you choose horses, and the race plays out, it creates a 30-digit binary number that will look something like this: 101100010000111001001000010001

That binary number determines whether you win a prize, and if so, how much. As the player, you have the option of picking your horses in the race, or having the machine randomly pick for you. If the machine does all the picking, then spits out the results, the experience looks and feels identical to that of a slot machine.

What’s The Difference? Value to Player

On the surface, there’s not much difference at all. Underneath, however, there’s one very important thing that sets these games apart, and that’s the theoretical return to player, or RTP. The higher a game’s RTP, the more likely you are to win; (or more appropriately, the less likely you are to lose).

Land-based class III slot machines (the real ones) can carry an average RTP of anywhere from 88% to 92%, depending where you play. Their online counterparts average 96% RTP. VLTs only pay an average RTP of 88%. Class II bingo slots can pay out as low as 80%. HHRs are impossible to judge, since they’re based on pari-mutuel wagering, but the minimum is generally 80%.