At the casino: Explaining how slot machines work

By The Careful Gambler

How do slot machines work? A good question! My gambling friend, Double Down Dan says ≥they work 24 hours a day, seven days a week, and 52 weeks a year without vacations, holidays or breaks. The perfect employee. No wonder the casinos love them.≤ On the other hand, my wife, Mrs. Careful Gambler, who loves slot machines, says when entering a casino: ≥They work fine, let me at them.≤

Let me then, explain how these computer chip driven devices work. No doubt you have been to lawn fetes and seen Prize Wheels, where a wheel having say 24 numbers on it is spun. On the booth counter there are the same 24 numbers, and to play you put a quarter on a number. If the wheel is spun and stops on your number, you win a prize, say a five dollar box of candy. The operator collects $6 [24 quarters], awards you the $5 box of candy, and has a profit of $1. This is a pay out of 83.7 percent and a hold of 16.3 percent (As explained in last monthπs article, these are percentage figures similar to poorer paying slot machines).

The slot machine doesnπt have a spinning wheel in it, but rather a unique computer chip called a Random Number Generator, or RNG for short. The RNG generates a random stream of well over a million different numbers, a string of numbers. Each number generated has no relationship to the prior number that was generated nor has it a relationship to the next number to be generated. Think of a gigantic spinning wheel and where it stops determines whether you win or lose and how much.

The RNG is totally random and therefore unpredictable. Each of these generated numbers has an associated computer instruction that directs the outcome or final position of the slot machine reels. The RNG stops streaming numbers when you hit the spin button or pull the machine arm. The associated instruction determines the outcome of your bet. Most of the numbers generated will result in no pay-out, say a bar and two blanks on a three-reel machine. Some of the generated numbers will result in a winning combination, say three-sevens, and therefore pay you some multiple times the number of coins bet. A very few of the millions of numbers that are possible will cause big pay-outs or jackpots. A mathematical assessment of all the possible outcomes, both winning and losing, determines the pay-out percentage for that slot machine. The same principle of operation applies to the slot machines that display characters like unicorns or monsters instead of bars or cherries or blanks. Whether there are three, four, or five reels, and whether you play one or 45 coins, the RNG, and when you stop it, determines the machineπs result. [I will explain how video poker machines work in a future article.]

So then, what will the total pay-out percentage be on your slot machine, the figure comparable to the 83.7 percent shown in the earlier cited Prize Wheel illustration? The manufacturer can program the pay-out percentage to be anywhere between the low 80s and the high 90s, depending on the direction from the casino. These pay-out figures are not released by our local casinos however, same statistics were once available from IGT, one of the worldπs largest manufacturer of slot machines. IGT reported that their popular machine, Red, White, and Blue could be programmed with a pay-out range of from 85.03 percent to 97.45 percent, dependent on the wishes of the casino. That would define the range possible on the local Red, White, and Blue slot machines.

Accepting the fact that your slot machine play is a random event dispels these false superstitions; MY MACHINE IS DUE!äSHE TOOK OVER MY MACHINE AND STOLE MY JACKPOT!äMY MACHINE IS IN A GOOD CYCLE!äTHAT MACHINE JUST HAD A BIG PAY-OUT AND SHOULD BE AVOIDED!...RUBBING THE FACE OF MY MACHINE WILL IMPROVE MY CHANCES!. All of these statements are false. The only thing that determines your machineπs result is the exact instant when you hit the spin button and the pay-out percentage programmed into your machine, nothing else. However if you enjoy talking to your machine, rubbing the screen, hitting the spin button with your lucky finger and so on, keep doing it, for gambling is entertainment. So until next issue, ENJOY YOUR GAMBLING.