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Understanding the Slot

As the casino industry expands, the same old slot-machine myths survive—many through a misunderstanding of how slots work

By Frank Legato


As casino gaming expands to new U.S. states, both physically and online, blogs and instructional websites continue to crop up to create new online communities of slot players.

The majority of the information on these sites is valid; many offer the same good advice about choosing slot machines, budgeting your bankroll and scrutinizing games online for free before spending your money.

However, there are still too many sites perpetuating old myths about slot play that, for the most part, grow from a misunderstanding of how slot machines work. One recent blog, for instance, noted that a 97 percent return-to-player or RTP—the now-common description of the game’s payback percentage—“means you’ll win back 97 percent of every wager.”

That’s not what it means at all.

A 97 percent RTP or payback percentage means that 97 percent of all wagers on a slot game—that’s all bets on a game, throughout the life of the machine, measured in years—will be doled out among all players that have played that game. You still need luck to nab a substantial chunk of that 97 percent of wagers.

The RTP percentages listed at online gaming sites and the payback percentages listed by manufacturers for casino slot machines are actually theoretical statistics arrived at by simulating millions of spins on a slot machine. Mathematicians map out possible results on a slot machine and assign them numbers. The game developer uses those maps to create a pay table, assigning appropriate portions of the possible results to wins on the pay table.

Symbols that create big wins are given a few numbers in the program; lower wins and blanks are assigned a bunch of numbers. Then come the simulations of years of play, and the calculation of a theoretical payback percentage or RTP.

Actual pay statistics have shown that a slot game will generally match its theoretical payback percentage within several weeks of play, not through the life of the machine. So these calculations work.

But again, they don’t mean you win 97 percent of the time. They mean everyone will collectively win back 97 percent of all wagers.

The simpler way I like to look at it comes from the easier-to-understand house advantage on table games. When a slot has a 97 percent RTP, that game has a 3 percent house edge.

You may find that level of RTP online, but good luck finding that in a casino. Most of those slots on the physical floor have a house edge more like 10 percent, many even more.

RTP, of course, is not the only cause of a myth surrounding slot machines that has survived. To their credit, most of the slot blogs get it right when addressing these ones:

  • A slot game is never “due” to pay out. The slot program is designed as a random selection of numbers generated by the random number generator. As such, each spin of the reels is an independent event selecting from all possible results in the game—which, by law, must be available on every spin. No one spin is related to any others. Therefore, it is impossible for a game to be “due” to become hot. Any given game can go weeks without returning a jackpot, and then go several more weeks. Or it can return several jackpots in a few days. You never know.

The only exception to this rule is in the new games that feature a “Must Hit By” jackpot. There are several games out there with this feature. It’s usually a mystery progressive jackpot, and under the meter it will say “Must hit by $500.” Well, if the meter’s at $495.75, you can say that machine’s “due.”


  • A new player who wins at the machine you just left did not “steal your jackpot.” This is true because of the sheer speed at which the modern random number generator generates the numbers in the program. Even when the machine is idle, the RNG keeps cycling through those numbers, at rates often exceeding 1,000 numbers per second. When a player hits the “spin” button, the computer freezes the sequence of numbers generated at that nanosecond, and translates it into a reel result. That all happens in an instant.

Therefore, if you’ve been sitting and losing spin after spin at a slot machine and give up with someone standing behind you waiting to play, just the several seconds it took for you to stop playing and stand up, and for the other player to sit down, insert money and begin playing means there is virtually no chance you would have hit that “spin” button at the exact same nanosecond the new player did, even if you had just kept on playing. He didn’t steal your jackpot. You would have gotten a different result.


  • The good games are not necessarily on the end of the bank. For decades, slot managers in casinos would draw players into the casino by placing the highest-paying games where they were most visible—on the ends of slot rows, or facing the casino entrance. This is not necessarily the case anymore. First, even in the past, there were as many slot officials who would bury the highest-paying games in the middle to minimize their liability as there were those who wanted to trumpet them.

But more significantly, over the decades, slot officials developed specific RTP policies for each denomination—pennies returning 90 percent; dollars, 94 percent, etc.—and they generally stick to those policies when buying machines. So, a penny game buried in the middle of a bank is going to return the same as a penny game on the end of the bank across from the nightclub or restaurant line.

There are other persistent myths, such as the value of alternating between spin button and handle on an old-style slot—it’s the same; the handle just pushes an internal spin button—but if you ever have any questions about what’s true or false about a slot, just shoot us a letter. We’ll get right back to you

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