You're welcome! In an 8/5 game, the jackpot would have to reach 37,704 coins to reach 100%, assuming you have to play 20 coins to win it. Assuming only 8 coins, the meter would have to reach 15,082 coins. On a 7/5 machine and 20 coins required the meter would have to reach, 46,956 coins. These figures assume you are playing the proper strategy for these pay tables with a per coin payoff for a royal flush of 800. As the jackpot grows some strategy adjustments are called for to more aggressively try for the royal. These adjustments were not calculated in this answer. It doesn't make any difference what the coinage is.

The older machines used to have three lines but the newer video slots can have up to nine lines. Buy-a-Pay: These are the most misunderstood machines in the casino. Each coin activates a different payout. Sep 05, 2018 A gaming industry expert explains how casinos' ability to hide the price of a slot spin ensures a reliable stream of revenue from even the savviest of gamblers. How slot machines work – and why. You can typically bet on 1 to 9 pay-lines (even though some have as many as 15 different pay lines), and multiple coins per line; thus, with nine pay-lines and five coins played per line, you would have a total bet of 45 coins (even in nickles, this can start to add up!).

Each frame in these video slots is weighted equally. Any given line is equally likely to produce any given combination. Thus, the return is the same regardless of the number of coins played.

Thanks for the kind words. I have barely heard of teams of slot players doing this. However, this is very common with progressive video poker players. There are teams of these professional players who routinely check the meters and when they find one high enough they call their teammates in an attempt to monopolize the machines until somebody hits the jackpot.
The problem with slots is that it is not clear to the player what the odds are of hitting the jackpot so it is not obvious what the jackpot size has to reach for the machine to become profitable. Plus, it probably rarely happens that a meter gets high enough to overcome the house edge.

If the odds against something are 4 to 1 then there are 4 chances it won't happen and one chance that it will. So, in this example, the probability would be 1/5. It doesn't matter what the probability is, if the events are independent then the past does not matter.

None of these factors matter. Walk away when you're not having fun any longer.

For variable-state slots, you have to know what the positive point is for that model of machine. For example, on the Piggy Bankin' slot machine, I think it becomes positive when there are about 40 credits in the bank. At that point the player is supposed to play one coin at a time until the bank is hit. The book Robbing the One-Armed Bandits by Charles Lund (1999) covers specific positive points for various machines, however many of the machines covered in that book are now hard to find.
As for how to determine when a progressive jackpot is unusually high, you'll either have to observe it over a long period of time or find someone who has done the same. For example, SlotCharts.com keeps data on progressive slots at online casinos. But even when a progressive slot is unusually high, it's impossible to know at what point it becomes high enough to be a positive-expectation game without knowing how the probabilities on the machine are programmed. In my section Deconstructing Megabucks I attempt to figure out when the jackpot is large enough to have a player advantage.
Update: Since this question was published, SlotCharts.com is blocked to U.S. traffic.

Thanks. This is a good question and I wish I had a firm answer. The exact answer depends on the theoretical return of both machines, and nobody ever reveals this information. Yes, you do get a better return in general on dollar machines than quarters, but you are giving up the max-coin bonus. I think the house edge will do down about 2% making the jump from quarters to dollars. However, without reel weightings, I can't tell you the cost of not playing max coins. My general advice is to find a slot machine without a max-coin incentive and then bet one coin at a time.

You’re right, the mathematical answer is that it doesn’t matter. I would choose the machine either randomly or based on environmental factors. My highest priority is that if there were any smokers in the vicinity I would sit as far from them as possible. Otherwise I would distance myself from any loud noises, including other players. If the machines were crowded I would pick an aisle machine, giving me a little more elbow room and one less neighbor.

I believe that most online slots have a fixed return, regardless of the coinage. This is unlike slots in real casinos, which return more the greater the coinage. What you should do depends on your priorities. If you want playing longevity then you should play as little as possible per spin. If you want hope for a big win then you should play as much as possible per spin. However the house edge is likely the same either way.

No. If your goal is a small win then you should be playing low volatility, high hit frequency games. I can’t suggest any particular games but look for ones with comparatively small jackpots. These will also help you to play longer.

I’ve been asked about these North Carolina slot machines so many times I’m tempted to fly there just to see them for myself. Yes, if they did give the probability of each symbol for each reel then an optimal strategy and a return could be fairly easily calculated. However I have never actually seen such a table and have never worked out the odds.

The odds are exactly the same on a one line, 10 line, and n-line video poker machine. When you get a trash hand in 100-play you can expect to get about 36% of your original bet back. In 10-play it is still 36% but there is more volatility. In 1 play it is still 36% but you can get lucky and get a high paying hand on the draw. In other words you are more likely to hit it big on the draw in single play, but at the expense of lots more non-paying hands.

For purposes of determining the game outcome the slot machine does not consider how many lines you bet or how much per line. The only thing that matters is the exact nanosecond you pressed the spin button. Random numbers drawn at exactly that time will determine the outcome, since the machine is picking numbers even when you’re not playing.

1st place: $1,000,000
2nd place: $150,000
3rd-6th place: $25,000
7th-8th place: $20,000
9th-50th place: $5,000

The cost is $25,000, and the tournament is limited to 50 players. It is easy to see the expected win is $30,000. However, it is a huge long-shot. What would be the required bankroll for entry to be a sound bet under the Kelly Criterion?

The Kelly Approximation is the advantage divided by the variance. The possible outcomes are a win of 39, 5, 0, -0.2, and -0.8 times the bet amount. The advantage is (1/50)×39 + (1/50)×5 + (4/50)×0 + (2/50)× -0.2 + (42/50)×-0.8 = 0.2.

The variance is Expected(win²) - (Expected(win))² = (1/50)×39² + (1/50)×5² + (4/50)×0² + (2/50)× -0.2² + (42/50)×-0.8² − 0.2² = 31.4192

So, the approximate optimal Kelly bet is 0.2/31.492 = 0.0063655 times the bankroll. For a full entry of $25,000, the required bankroll would have to be 25,000/0.0063655 = $3,927,400.

However, for large bets like this, I think it is worth the time to find the exact optimal Kelly bet. Next, find the bet size b, which maximizes the expected log of the bankroll after the tournament, as follows.

Log of bankroll after tournament = (1/50)*log(1+39×b) + (1/50)*log(1+5×b) + (4/50)*log(1) + (2/50)*log(1-0.2×b) + (42/50)*log(1-0.8×b)

There is no easy way to solve for b. Personally, I recommend the 'Goal Seek' feature in Excel. The answer will come out to 0.0083418. So, the exact Kelly bet should be 0.0083418 times your bankroll. To justify the $25,000 entry fee, your bankroll should be $25,000/0.0083418 = $2,996,937.

1. Does this take into account the unknown house edge on the slot machines?

2. What would be the playing strategy for the best overall return? Could you just sit back and not gamble, and hope that the other 49 players all end up behind, while you break even and take the grand prize of $1,000,000?

Do Slot Machines Spin Different At Different Bet Levels Calculator

Slot tournaments are always held on dedicated tournament machines. Usually these machines don’t accept bets, so your balance will either stay even or go up, after each play. So it doesn’t make any difference what the return is; the more you play, the more you can expect your balance to go up. Even if you had to play conventional slot machines, I would still bet as fast as possible, stopping only if I got a jackpot large enough to likely win the tournament. The reason is that it is very unlikely that 49 out of 49 players would be negative.

Interestingly, there was once a slot tournament at Caesars Palace where they gave a prize to the person who finished last. However, they didn’t announce this rule until the award ceremony. If you somehow knew of such a rule, indeed, it might be best to not bet.

I would play once on a $5 three-reel single-line game. Win or lose, walk away after one spin.

Slot machines are the most popular game in any casino. Sure, people bet more on the lottery, and the worldwide sports betting market is huge. But slot machines are the game du jour in most casinos, especially in the United States.

Sadly, slot machines games also offer the worst odds in the casino except maybe for keno. The compounding effect of making hundreds of bets per hour at the slots make these games a bigger moneymaker for the casino than keno.

There’s no science to playing slots. You put your money in, spin the reels, and hope for the best. The only decisions you make are which game to play and how much to bet.

This post covers how much you should bet. You’ll often hear so-called gambling experts say you should always place the maximum bet on slot machines.

This isn’t true for most games.

There Are Two Kinds of Max Bets on Slot Games

You’ll only find one “Max Bet” button on a slot machine game, but some games allow you to adjust the number of paylines you bet on. These are older games. They preceded the guaranteed “243 ways to win” games.

The first time I saw one of these games, a friend of mine called them “penny slots.”

The minimum bet was 10 cents per payline and the game had 25 paylines. The minimum bet was, to my way of thinking, $2.50. You could never bet just a penny on that “penny slot” game.

The maximum bet was $1 per payline. This was a sneaky way of getting the players to lay down more money. If you hit “Max Bet” on that machine, it took $25 in credits from your balance.

The More Complicated the Slot Game, the Less Likely You’ll Win

If you don’t understand how much you’re betting when you push a button on a slot game, there’s something wrong with the game. Perhaps the gaming industry just went through a phase of bad design.

But just because a slot machine game has multiple paylines, you shouldn’t assume that you’ll lose money if you bet on fewer paylines. Each bet on each payline is a separate bet, so playing all the paylines at once might make you more likely to see a winner. But you’ll also see more losing spins on the other paylines to compensate (in the long run, anyway).

The game is still programmed to spin as if all the paylines are active. I watched in horror, as that $25 bet spun the reels. I got lucky and the machine paid a low prize. I didn’t lose $25.

You can save money on a slot machine like this in two ways.

1. You can bet on fewer paylines.
2. You can lower the size of your bet.

My buddy disabled all the paylines and played $1. We saw a big prize combination come up but it didn’t pay anything. It was on a deactivated payline. There was no pattern on the one active payline.

A Few Older Games Increased Your Probability With Your Bet Size

This kind of game worked in the opposite way. You didn’t disable or enable paylines. The game’s help screen said some features were only enabled for the max bet.

We deduced that meant the theoretical return to player was calculated only for the max bet. And if the game wasn’t allowing you to use all the features with lesser bets then it must have had a lower RTP.

I went back to play some blackjack that night but my friend stayed and played that game. He did okay, not great. He said it made a big difference to play the max bet.

A Basic Slot Game Doesn’t Change the Probabilities

Whether it’s a 3D video slot with monsters running around the screen or just a classic three-reel game, if the slot game doesn’t disable paylines or require max bets, then the probabilities don’t change.

You can bet the minimum or maximum credits, and it won’t affect the outcome of the game. You simply change the number of guaranteed spins you can play.

If you have $300 and a game has a $1 minimum, you can play that game 300 times. If you make a maximum bet of $5 on every spin, then you can only play the game a maximum of 60 times (if you lose every time).

This makes a difference to some players. Other players say you’re not going to lose 60 times in a row, so why worry about that? Bet the max and get the most from your prize.

Most Progressive Slot Games Only Pay on Max Bets

If you’re playing a progressive slot game, then you need to make a maximum bet. I’ve seen a few games with multiple progressive jackpots where you only needed a max bet for the biggest jackpot.

If you have two versions of the same slot game, one is progressive and the other is not, you might as well play the max bet on the progressive version of the game.

Progressive slot games have a mixed reputation. I’ve talked to people who refuse to play them. They’re convinced the payouts are less on progressive games.

And I know people who almost exclusively play progressive slot games. They would rather win a big prize beyond whatever the machine itself pays. They don’t have to win $1 million if they can come away with a few thousand.

I’ve seen it play out both ways. I’ve never been in a casino where someone won more than $10,000.

The Math Says Max Bets Put You Ahead Faster

Assuming you find a slot machine that pays reasonably well, maybe it’s on a “hot” streak despite its regular RTP, why not play only max bets?

If the maximum payout is 1000x your bet, you’ll make $999 on a $1 bet or $4995 on a $5 bet. That’s a really simple equation, so why doesn’t everyone bet that way?

If you’re down to your last $20, you may decide to “roll it up. ” But what’s the difference between rolling up $20 and rolling up $200?

It comes down to how many spins you can guarantee yourself. This is a psychological game we play with ourselves. The odds of winning on the next spin are the same regardless of how much you bet.

There Is Another Advantage to Not Making Max Bets

If you want to play a lot of different games and you don’t have an unlimited bankroll, then playing minimum bets allows you to spread your time around.

Some players like to test the games when they visit a casino for the first time. They make a decision based on luck.

I remember watching a man approach a slot machine late one night. I was getting ready to leave. He put a dollar in the machine and spun the wheels.

Do Slot Machines Spin Different At Different Bet Levels Indicate

He went down the line of machines until one of them paid. There, he stopped and began playing.

Conclusion

Slot game designs have become more polished, but their rules are less confusing. People want to push a button and win some money.

I think caution is only warranted if you’re unfamiliar with the games and you don’t know immediately if they have any special rules. It’s always a good idea to read the pay tables first.

And if you’re a little confused by the game rules, then only play minimum bets until you understand what the game is doing.

There’s no need to rush into max bets if you’re not ready to take that chance.