How Online Slots Work

online slot

Online slots are captivating games that don’t require much brain work. Their design is based on instant gratification, which is what keeps players coming back for more.

These games have a lot more to offer than the classic fruit machines of the past. They are available for a variety of wagers, and they can feature dozens of pay lines.

Random number generator

The random number generator is a crucial part of online slots, and it’s important to understand how it works. It’s a protected program that runs a mathematical algorithm to generate a sequence of numbers. This sequence is then translated into symbols on the reels.

Unlike dice or coin flips, where natural entropy and manual human exertion play a role in the outcome, computer-generated results are completely unpredictable. This is what makes the RNG so valuable. It’s the same technology used to select winners for lottery games, board and card games, sports competitions, and even jury selection. It’s also the technology behind most video games and computer programs. It’s based on cryptographic hash functions and other mathematical algorithms. The random numbers are generated constantly, and the software determines what should happen on the machine’s reels when players press “spin”. The results are always different.


Online slot games are similar to physical slots in that you put in your money, click the spin button and wait for the results. The internal mechanics, however, are much more complex. They use software based random number generators to determine the symbols that appear on the reels after each virtual spin. These systems are tested by independent agencies to ensure they are unbiased and untampered with by casinos or players.

Reels are vertical lines that hold 3-5 symbols and are used in combinations to create winning paylines. You can see the paylines in a game’s help screen or in the payout table. The paytable will also list the game’s Return to Player (RTP) and variance rates. The higher these values, the better your chances of winning are.


Standard symbols are used to represent the regular paying icons in online slot games. Typically, they offer payouts when they form an eligible payline and are often represented by card values like A (Ace), K (King), Q (Queen) and J (Jack). Occasionally, special symbols will be added to the reels to enhance the experience. These include Stacked symbols that take up more space on the reels and increase your odds of forming a winning combination, and Multiplier symbols that double the size of your wins.

Other special symbols include Wild symbols, Scatters and Bonus symbols. The latter usually trigger a bonus game, which is where big wins are lurking. These bonus games can be highly entertaining and creatively designed to fit a slot’s theme.


In online slots, paylines are lines that cover one position for each reel and must match in order to form a winning combination. The more paylines a slot has, the higher its winning potential but also the more it will cost to spin.

Some online slots have fixed paylines while others allow players to choose the number of paylines they want their bet to cover. Regardless of how many paylines you choose, it’s important to know that only active paylines count towards winning payouts. If you land a winning combination on an inactive payline, you will not get paid. However, if you win with three or more matching symbols on an active payline, you will be paid out.

Bonus rounds

Online slot games use bonus rounds to add to the fun and offer players an additional payout. These rounds can be free spins or a separate game that shares a common theme with the base game. Some of these games require a specific combination of symbols to trigger, while others are randomly awarded.

These bonus games often take place on a second screen and can be anything from interactive board games to simple pick-and-win activities. Some of them even have progressive jackpots that build up over time.

Some slots also incorporate multipliers that multiply your winnings by a fixed amount. These can be very lucrative, as they can increase your chances of hitting the jackpot. These extra features are meant to break up repetitive spinning and give the player something to look forward to, releasing a rush of adrenaline each time a bonus feature is triggered.