There are thousands of different slot machines to choose from at online casinos. Some are more popular than others, but all work in the same way. Each spin costs a certain amount of virtual coins and the outcome can be anything from winning money to going to a bonus round. It’s important to understand the differences between different slots, so you can select one that’s right for your preferences and bankroll.

Unlike the old electromechanical devices, where you had to manually adjust the coin size and number of paylines, the operation of modern online slots is entirely automated. The software determines the outcome of each spin using a random number generator (RNG), which is independently tested by external experts to ensure that it is fair and unbiased. The result of each spin is displayed on the reels, and if there are matching symbols on active paylines you will receive a payout. The amount you win is then added to your balance.

The first thing to look for when selecting a slot is its theme. While some may have a more traditional feel, with rows of classic symbols over a few reels, other games use a more modern approach with Megaways or high volatility. Regardless of the theme, all online slot games have the same mechanism at play, so the choice is really about game variety.

Another factor to consider is the variance, which is a measure of the size of wins compared with how frequently they occur. This is important because a low variance slot will pay out more often but with smaller winnings, while a high volatility slot will pay out less frequently but with bigger wins. Some slots also offer a balance between the two.