Slot Machine Odds Guide

Slot Machine Odds Guide

Slots are hugely popular at brick-and-mortar casinos and gaming sites, with thousands of titles to choose from. The cash prizes on offer vary significantly, but your chances of winning depend on the odds.

In this guide to slot machine odds, we’ll explore how odds work, how to calculate them, and more.

How Do Slot Machine Odds Work?

When discussing slot machine odds, we’re referring to the probability of a game awarding a particular payout. Winning on a slot requires that you match identical symbols (usually at least two or three) on a payline or across consecutive reels.

Generally, symbols that award lower payouts are more likely to land on the reels, so the odds of winning with these are higher. But higher-paying symbols are rarer and have lower odds of creating a win. The same applies to Wild symbols and bonus symbols.

The number of winning combinations in a game (usually thousands or even millions) and the prizes awarded for these determine the odds offered by a slot machine. While odds are unconnected to the Return to Player (RTP) and volatility of a slot, games with a high RTP and low volatility tend to bring higher odds of landing a winning combination than slots with a low RTP and high volatility.

How to Calculate Slot Machine Odds

Calculating slots odds can be difficult, based on the sheer number of possible winning combinations in a game. To do this, let’s use a simple example.

We have a classic slot game with 3 reels, 1 payline, 6 fruit symbols, and 1 Bonus symbol. There are 6 symbols on all 3 slot reels, creating 343 total outcomes. As you need one symbol type to land on every reel, there are six possible outcomes.

Three Bonus symbols on the payline have 1 combination, and there are 18 possible combinations for 2 Bonus symbols on any reels. For Bonus symbols landing on any reel with fruit symbols, the number of possible combinations is 108.

If we add these numbers together, we get a total of 133 possible combinations for this game.

To calculate these slot machine odds, we simply divide the number of winning combinations by the number of possible outcomes. In this example, the odds would be 0.3877 (38.77%).

You can use this formula to calculate slot machine odds on any game. It can be complicated at first, but it should become easier over time.

4 Things You Need to Know Before You Play Slots

When you’re looking for slot machines with the best odds online, there are a few important factors to bear in mind before you dive in.

Fruit Slot Machine

Random Number Generators

Online slot machines use a random number generator (RNG) to decide the result of spins and ensure that they’re always random. The outcome of one spin won’t be affected by the one before or after it. That’s an essential fact to understand when learning how to play slots.

Some players may feel that they’re on a winning or losing streak if they go for many spins without a win or loss, but that’s all down to the RNG. Just because you win on multiple consecutive spins doesn’t mean you definitely will or won’t on the next. Each spin stands apart, so even if you feel convinced that a slot is set against letting you win, the RNG could award a prize seconds later.

Random number generators are audited and inspected to make sure that they work properly. This is crucial to ensure that players have a fair chance of winning.

Slot PAR Sheets

Slot PAR sheets provide a comprehensive breakdown of a game’s maths model. These are typically confidential, as they reveal how regularly bonus features will be triggered, symbol hit frequency, hold percentages, RTPs, and more. Programmers use slot PAR sheets when working on games.

Payouts and Combinations

In slot machines, payouts and combinations go hand in hand. Each slot uses a number of symbols, and each one will award a prize if you match them in a specific arrangement.

There may be just a few possible winning combinations in a game, or there could be tens of thousands. Payouts vary depending on the symbols matched and how many form a winning combination.

Return to Player Percentages

Return to Player percentages show how much a slot is expected to pay out over time. The average for slots is 96%. That means a game will theoretically pay out $96 for each $100 wagered on average. RTPs are calculated by game providers running millions of simulated games.

Jackpot Slot Machine

Modern Slots Payout Odds

As modern slot machines use complex RNGs to determine the result of each spin, the latest games can have thousands upon thousands of outcomes. However, they all follow the same structure as the sample we explored earlier.

Slot Machine Volatility

A slot machine’s volatility refers to how often wins are triggered and their size. Highly volatile slots usually award large prizes sporadically, but low-volatility slots offer small payouts frequently.

It’s vital to check the volatility of any slot before you play, so you know the element of risk involved. You may prefer to win little and often, or you might focus on spinning for bigger payouts despite the lower likelihood of winning.

Final Thoughts

Slot machine odds can be a complex area, especially if you’re a newcomer to the world of slots, but calculating them can help you learn more about a game before you start playing.

Whichever slots you choose, always remember to gamble responsibly. Only bet money you can realistically afford to lose, and monitor your bankroll carefully.

If you’re ready to start spinning but you’re not sure where to play, check out Gambling Zone’s guide to the best slot sites online.


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