Online Slot is one of the most popular games in an online casino. It’s easy to play – all you have to do is place your bets and click the spin button. The reels then stop at a random point and you win if you hit a winning combination. But behind this simple interface, there is a lot of science: from the fact that online slots are based on probability and not pre-determined results to the RNG technology that guarantees a random outcome for each spin.

The RNG (Random Number Generator) is a complex algorithm that churns out ten thousands of numbers per second. Each of these is then associated with a specific symbol or symbols on the reels. When you spin the wheel, the RNG picks a random number from this pool of numbers and associates it with the particular combination on the reels.

The rest is simple math – a RTP value of 99% means that for every dollar you put into the machine, it will pay back a certain percentage over time. Variance is another factor that determines how often and big the winnings are, though this has to be taken with a grain of salt – a low variance slot may pay out small amounts very frequently but will never be as exciting to play as a high variance game. Online casinos also offer a range of bonus features to help players win more often. These can include regular multipliers such as a 2X or 3X wild symbol, or progressive ones that increase with each successive win.