What is a Casino Random Number Generator | May 2024

A random number generator (RNG) is a mathematical algorithm ran on a device or software to generate a sequence of numbers at random. In table games played at land based casinos, random results occur naturally in cards dealt from a shuffled deck in blackjack or dice bouncing on a craps table.

Online casino games use RNG software to reproduce that randomness in a digital form. This page will cover everything you need to know about how random number generators work and how they are used in your favorite casino games.

HOW DO CASINO RANDOM NUMBER GENERATORS (RNGs) WORK?

Casino game developers incorporate RNG into their games to generate numbers, symbols or sequences into a random and unpredictable order. To ensure security and fair play, casino RNG software does not predetermine a string of outcomes.

Instead, the number generator is continuously shuffling through thousands of possibilities per second, and your outcome isn't locked in until you hit the "Spin" or "Deal" button.

To illustrate this concept, let's compare the difference between how single deck blackjack works at land based casinos and online casinos. In a physical casino, the deck of 52 cards is shuffled into a random order before the cards are dealt. The odds that the first card dealt to you is an ace are 1 in 13 (7.69%), since 4 out of 52 cards are aces.

A random number generator for online casino blackjack is generating thousands of potential outcomes for your first card until you click deal, and the next card generated is the one you receive.

This RNG algorithm would be weighted to give each of the 52 cards in the deck an equal chance of being generated, so your odds of being dealt an ace first are still 1 in 13, the same as they are in live casino games.

HOW DO THEY WORK FOR SLOT MACHINES?

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Random number generation for a slot machine works by assigning each symbol in the game a numeric value, and then generating random numbers to determine where those symbols will land on the reels.

For example, imagine a simple three-reel slot machine that has three symbols; a cherry (assigned the number 1), a lemon (2), and a bell (3). Another possible outcome on this slot game is a blank on the pay line, represented by a 0. The random number generator shuffles through thousands of random number sequences until you press the spin button, locking in the sequence of 2-0-2. On the screen, you see a lemon land on the first reel, a blank on the second reel, and a lemon on the third reel.

This is how RNG algorithms work for both retail and online slots. Modern slot games are of course far more complicated than the example used above.

But all of those flashy symbols, paylines and bonus features are powered by a random number generator churning out a sequence of numbers to tell the symbols where to land when you hit "Spin".

WHAT COMMON TYPES OF RNGs EXIST?

The two most common types of RNG tools are true random number generators (TRNG) and pseudorandom number generators (PRNG).

This educational section will cover the differences between these two RNG types and how it applies to online gaming.

TRUE RANDOM NUMBER GENERATORS

A true random number generator relies on physical phenomena that are known to be unpredictable and uses measurements of these completely random events to produce random numbers.

Natural phenomena like thermal noise or radioactive decay can be measured with advanced tools and converted into a sequence of numbers. Because these phenomena are completely unpredictable in nature, numbers generated by them represent true randomness.

While TRNG produces the most truly random numbers, there are some downsides that make it an impractical choice for casino operations.

Recording and processing physical phenomena is technically difficult and expensive, and virtual casino games require numbers to be generated in large volumes at high speeds.

These drawbacks are among the reasons that most casino operators use a pseudorandom number generator instead.

PSUEDO RANDOM NUMBER GENERATORS

A pseudo random number generator is an RNG algorithm that uses mathematical formulas to emulate true randomness. These algorithms start with a small number called a seed number that can generate random numbers quickly and efficiently.

PRNG is much easier to scale out for advanced online games and computer simulations. The sequences of numbers produced are not unpredictable like TRNG as they are based on the algorithm's seed number instead of natural phenomena.

But they work well for RNG based games as they can deliver true statistical randomness and a fair gaming experience at a fast pace.

WHICH CASINO GAMES USE RANDOM NUMBER GENERATORS?

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All online casino games and some land based games use RNG to determine outcomes and to simulate game elements like cards being dealt or a roulette wheel spinning.

Here are some of our examples of the application of casino RNG.

SLOT MACHINES

As detailed in a previous section, the random outcome of each slot spin is based on a sequence of numbers that each have symbols assigned to them.

Valuable symbols like wilds and bonus triggers are programmed in the RNG algorithm to appear less frequently than weaker symbols, which is why it is difficult to land a big winning combination.

AUTOMATIC TABLE GAMES

Online casino table games and electronic game terminals on in-person casino floors use RNG for cards, dice, and wheel spins.

Unlike slots that have a casino edge due to some outcomes being programmed to occur more often than others, the house advantage on table games comes from the rules of the game.

A pseudorandom number generator ensures that digital dice, wheel and card games have the same statistical odds as their physical counterparts.

VIDEO POKER

RNG is responsible for determining the hand you are initially dealt and your redraw cards when playing video poker.

CRAPS

When playing craps at online casinos, dice rolls are determined by RNG. The odds of rolling specific numbers are the same online as they are at physical tables.

LOTTERIES & BINGO

In-person lotteries and bingo games pull winning numbers from a machine that shuffles the balls up before one is selected.

Digital versions of these games emulate the same process using RNG.

KENO

Keno numbers are chosen at random by RNG on electronic formats of the game found online or on gaming machines in retail casinos.

THE CONNECTION BETWEEN RNG & RTP

Return-to-player (RTP) percentages are directly correlated to the RNG algorithms used in virtual games.

Because the RNG is programmed to replicate fair dice in craps or to deliver bonus features at a pre-determined frequency, software providers can accurately measure a player's long-term RTP.

WHAT IS RTP?

RTP is the theoretical return that an online casino game should deliver to a player in the long run.

A game with a 95% RTP is expected to return $95 in winnings for every $100 wagered.

Short term results will vary based on random chance, but long term, the game's RNG settings dictate what its RTP will be.

IS IT POSSIBLE TO OUTSMART A CASINO RNG?

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There is no strategy that can outsmart RNG or overcome the house edge of a casino.

There are strategies that you can use to improve your short-term winning chances such as choosing games with high RTPs and managing your bankroll properly to withstand cold streaks.

Over the long run however, the RNG will provide a fair online gambling experience that has a casino edge by design.

WHY RNG CERTIFICATION IS IMPORTANT

RNG certification verifies the fairness and integrity of the games used by an online gambling site.

Regular audits and testing are important to confirm that the RNG on a casino's server is secure and working properly.

RNG AUDITS FOR GAMING SOFTWARE

An independent RNG audit involves comprehensive testing from a third party that is not associated with any online casinos or software providers.

Receiving RNG certification from an independent auditor is essential to promoting fair play, shielding against fraud, and complying with local regulations.

CASINO RNG TESTING

In addition to independent audits, online casinos should also conduct statistical tests to confirm that the RNG software produces random numbers at the correct rates.

Agencies can test datasets compiled over a large number of events to make sure they align with expected results.

RNG-BASED CASINO GAMES VS. LIVE DEALER GAMES

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Popular table games like blackjack, baccarat and roulette are available on many online gaming sites as both RNG-based electronic games and live dealer games.

The same rules and odds apply to both versions of the game, but there are some pros and cons to each one.

RNG CASINO GAMES

Pros

  • Faster gameplay with no delays
  • Favorite games are always accessible
  • Larger variety of games and themes

Cons

  • No social interaction
  • Sights and sounds less satisfying than the real thing

LIVE DEALER GAMES

Pros

  • Interact with fellow players and real dealers
  • Replicates the in-person casino experience
  • Watch the cards dealt and the wheel spin in real time

Cons

  • Fewer games and open seats available
  • Slower gameplay with wait times in between each round

STRATEGIC TIPS FOR PLAYING WITH CASINO RANDOM NUMBER GENERATORS

Playing RNG-based games at the casino can be a great source of entertainment when enjoyed responsibly.

To get the most out of your casino gaming experience, consider these strategic tips.

PLAY THE DEMO

Many legal online casinos including DraftKings allow you to play demo versions of slots and virtual table games with play credits.

You can use demos to practice correct strategy for games like video poker and blackjack that have higher win rates when played optimally.

And on games of chance like slots, you can get a feel for the machine's volatility and payout frequency before you risk real money on it.

START WITH SMALL BETS

Whether you are playing land-based games with real cards or RNG-based games online, random events always occur in an unpredictable order.

Your RTP on a slot may be 96% in the long run, but in one sitting, you can never know what to expect.

By starting with a small bet size, you can test out a game and preserve your bankroll before deciding whether or not to invest more.

SET A BUDGET

Before you begin a gambling session, set a budget for yourself with an amount that you can comfortably afford to lose.

Stick to that budget and plan your bet sizing throughout the session accordingly.

If you follow this strategy, you'll never lose more than you can afford to and won't get into bad habits like chasing losses with irrational play.

CLAIM BONUSES

Claiming online casino bonuses is a great way to increase your gambling bankroll with no added risk.

For example, using a 100% deposit match bonus on your initial deposit at a new casino, you can immediately double the amount of casino credits in your account to play with.

Visit our best online casino bonuses page to see what offers are currently available in your area.

RESPONSIBLE GAMBLING WITH RNG CASINO GAMES

The key to responsible gambling on casino RNG games is control.

Set responsible daily, weekly, and monthly limits for how much you can play. Choose amounts that you can comfortably afford to lose and adhere to these limits at all times.

Being mindful of your limits should help you to keep your pace of play and bet sizes under control.

If you ever feel yourself losing control, don't hesitate to take advantage of the responsible gaming resources that are at your disposal.

RESPONSIBLE GAMING RESOURCES

Online casinos have multiple responsible gaming resources available including deposit limits and self-exclusion programs.

Contact customer service for assistance in utilizing these resources. You can also seek out help for problem gambling 24/7 with the National Problem Gambling Helpline.

CASINO RANDOM NUMBER GENERATOR FAQs

Do you still have questions about casino random number generators? Find answers to some frequently asked online gaming RNG questions below.

ARE RNGs USED FOR ONLINE CASINO GAMES?

Yes. RNGs are used to produce fair random outcomes in online casino games including slot spins, cards dealt, and dice rolled.

HOW DO I KNOW IF RNG CASINO GAMES ARE RIGGED?

Reputable online casinos are audited by independent third-party services to verify their authenticity and fairness. For more details, you can ask your online casino's customer service team to provide you with information on its RNG certification process.

DO ODDS CHANGE IF A SLOT HASN'T WON BIG IN RECENT PLAYS?

Not in general. The random number generator ensures that each spin is an independent event with pre-determined odds of a bonus or jackpot being awarded. Previous spins have no impact on the odds of the current spin.

"Must hit" jackpot machines are an exception. In the event that a slot advertises that a jackpot or feature must be awarded within a certain time frame or number of spins, the likelihood of winning that award does increase as the "must hit by" criteria gets closer.

CAN I CONTROL THE OUTCOME AT ALL OF RNG CASINO GAMES?

You can not directly control the outcome of RNG games over the long run. You can however use strategies to improve your chances of winning in a single session.

Examples include playing optimal strategy in blackjack or betting small to avoid running out of money before a machine awards a big win.