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Understanding the Mathematics of Slot Games: How RTP and Variance Affect Your Winnings?

Slot games are widely popular due to their thrilling nature. Unlike skill-based games, such as poker or blackjack, slot games rely solely on chance. Players place their bets, spin the reels, and await the outcome without needing any particular skill or strategy.

However, delving deeper into the world of slots reveals fascinating insights into the mathematics that control their operation. Understanding the mathematical principles behind slot games can empower players to make more informed decisions regarding their wagers and optimize their overall gaming experience.

Whether playing in a physical casino or enjoying countless slot games online, the underlying mathematics remain consistent. Mathematical principles ensure fairness and randomness in the outcomes of the games. Online casinos often provide detailed information about the mathematical aspects of their slot games, such as the return to player (RTP) percentage. Additionally, they employ advanced random number generation (RNG) algorithms, which generate unpredictable and unbiased outcomes for each spin.

This article explains the two key mathematical concepts related to slot games: RTP and Variance and discusses how these concepts affect your winnings.

Explaining RTP

RTP is the shortened and popular form of “Return to Player,” which refers to the amount of payout players receive in the long run from slot games. RTP is measured in percentage, typically from 93% to 98%, and the house takes the remaining 2% or 7% as profit. Therefore, understanding RTP might be the reason behind winning big slot games.

However, the average slot RTP is 96%, and the specific ratings can vary depending on different casinos and the games players choose. Players prefer slot machines with higher RTPs, providing better gambling experiences. For instance, let’s assume a player places a $10 bet on a slot machine with a 96% RTP. In this case, the player would expect to receive $9.6 in return.

The Role of the RTP in Determining Player Payouts

Players can expect lower payouts if the slot game’s RTP is low, typically between 93% and 95%. Conversely, slot games with medium to high payouts, ranging from 96% to 98%, provide players with a higher chance of winning big.

However, choosing the right RTP depends on players’ priorities and preferences, which can include the following factors:

  • Players’ budget: Those with tighter gaming budgets often opt for games with lower RTP ratings, as they provide longer playing sessions and entertainment value, even if the payouts may be lower. In contrast, players with bigger budgets might seek games with higher RTPs to maximize their winning potential.
  • Player type: Some gamers are more interested in the gameplay and overall experience than solely focusing on payout percentages. For them, the entertainment value and features of the game may be more important. On the other hand, others are enticed by the potential thrill of winning big and prefer games with higher RTPs to increase their chances of hitting significant payouts.

Finding Slot Games’ RTP

While it is indeed possible to calculate the Return to Player (RTP) of a slot game, online casinos typically provide this information publicly. It is important for players to review the Terms and Conditions section of a specific slot game to determine its unique RTP before wagering real money.

Explaining Variance

Slot machines’ variance is also an important mathematical concept that indicates the size and frequency of winning opportunities in different slot games. Slot game variance gives players an idea about the risk rating of a specific game.

The Different Types of Variance

Slots games’ variance is classified into three main categories:

  • Low Variance: Slot games with low variance provide players with more frequent winning opportunities but smaller payout sizes. This slot type suits new bettors and bettors with a small budget. The minimum betting value is lower than games with higher variance, and these games allow players to score reasonable profits.
  • Medium Variance: Medium variance slots allow players to score even higher profits, yet the payout frequency is lower than the previous category. This type is perfect for moderate players wanting to take additional risks and increase their chances of winning.
  • High Variance: With high-variance slot games, players have the potential to win really big profits, but the winning frequency is the lowest among the other types. Therefore, hitting a high profit from the beginning is almost impossible. It takes some time to win with these games, so players should set enough budget to avoid running out of money.

The Relationship between RTP and Variance

Understanding the relationship between RTP and variance helps players know how to choose a game that suits them. While RTP and variance refer to different aspects of slot games, combining them helps maximize winnings.

In other words, choosing a game with high RTP and high variance increases the chances of winning big, especially for high rollers looking to earn a fortune. On the other hand, games with lower variance yet still offer high RTP allows players to make moderate winnings while taking advantage of a higher RTP.

There are other helpful techniques for players to maximize their winnings, such as:

  • Choosing the game that offers the highest RTP possible
  • Trying the specific game through the free version first
  • Setting a fixed playing budget and sticking to it


There are many tips to help new players maximize their online casino experience. And understanding the concepts of RTP and variance might be on top of these tips. A high variance rating and high RTP increase winning opportunities. However, it’s important to remember that higher ratings also come with bigger risks.