
The most profitable slot machines have low variance (volatility) and high RTP (return to player, meaning the return to player should be over 96 percent).
Low, high and medium volatility levels are available. It indicates how often the wins fall out. Although wins are rare, with low variance they do happen. Even though prizes rarely fall out at high volatility, they always fall out by a large amount.
What is RTP (Return to player), how to calculate it and where to check it? RTP (Return to player) is an indicator, which is indicated by the provider in the description of the machine and which can be checked during 100 spins.
The average amount of money that the client pays out over a long period of time is called RTP. In casinos, the payout to the player is displayed as a percentage, for example, 96.10%, 95.69%, 98.56%, 95.43% and so on. The mathematical advantage of a casino game is represented by the RTP figure.
For example, there is Sticky Bandits slot released by Quickspin provider in 2017. The developer reports that the RTP is 96.58%. This means that for every $100 the casino pays out an average of 96.58%. Obviously, the player’s return cannot be calculated in 2-3 spins. It is a figure that demonstrates a mathematical advantage. There is a risk that you will either hit a winning streak and make a profit, or hit a losing streak and lose.
A player can calculate how much a slot will win based on the RTP. The best online casino slots usually have a return rate above 96 percent.
The RTP of online slots at casinos does not depend on the spin history of the game. In fact, the RTP is created by computer algorithms that trigger spins more than a thousand times in a short period of time.

Depending on the type of gambling entertainment, the return percentage in casinos varies as follows:
- online slots – from 93% to 99%;
- European roulette – 97.30%;
- American roulette – 94.74%
- classic blackjack – 99.40%.
Slot machines with a three-reel, piamtibar or seven-reel set of reels may have additional features and customizations. Depending on the manufacturer, there may be different options:
- doubling level (risk round);
- wilds and scatter, which provide additional symbols;
- multipliers, which increase the odds of winning;
- respins;
- buy spins;
- exit to an additional round;
- freespins (free spins) and other functions.
Such parameters, of course, are taken into account when calculating the RTP of slots for the casino.