How Slot RNGs Work, on the Example of Red White & Blue by IGT

In previous articles on Casinoz, we considered various matters of slot machine construction and operation, trying to dispel the most popular myths and misconceptions. We gave recommendations on choosing slots, described betting strategies, explained bankroll management basics, etc. However, we still do not think that all readers fully understand how modern slots work, how winning combinations are formed, and why you can trust games from famous software providers.

In this piece, we will define step by step the essential aspects. To clarify, we will take IGT's Red White & Blue slot as an example.

This slot is available in most land-based casinos in the United States. Also, we will show the calculations by Michael Shackleford, the author of the reputable website Wizard of Odds. We hope this information will fill some gaps in your knowledge about slot machines.

How Casino Slots Work

We will start by reminding you that the basis of any modern slot machine is a random number generator (RNG), which determines the outcome of each spin. No pattern or algorithm is used in its work.

So, each round is unpredictable and independent of other spins. If you play on machines from reliable manufacturers and independent auditors monitor the slots, you can be sure that no one knows what combination will land on the reels in the next spin.

After a player makes a bet and starts a new gaming round, the RTG produces a number for each real, which defines the display of various characters on it. In other words, the result is known only at the moment after the player presses the spin button.

Red, White & Blue Slot by IGT

We now turn to Red, White & Blue to clarify some details from its example. The paytable of this slot machine is as follows.

WIN	1 COIN	2 COINS	3 COINS
Red 7, white 7, blue 7	2400	4800	10,000
Red 7, red 7, red 7	1199	2400	5000
White 7, white 7, white 7	200	400	600
Blue 7, blue 7, blue 7	150	300	450
Any 3 sevens	80	160	240
1 bar, 2 bar, 3 bar	50	100	150
3 bar, 3 bar, 3 bar	40	80	120
2 bar, 2 bar, 2 bar	25	50	75
Any red, any white, any blue	20	40	60
1 bar, 1 bar, 1 bar	10	20	30
Any 3 bars	5	10	15
Any 3 reds	2	4	6
Any 3 whites	2	4	6
Any 3 blues	2	4	6
Blank, blank, blank	1	2	3

In the Red, White & Blue gaming machine, the RNG can create 64 possible outcomes. Each of them means the display of a particular character on a separate reel. Here is the table illustrating the procedure:

STOP NUMBER	REEL 1	REEL 2	REEL 3
1	2 bar	2 bar	2 bar
2	2 bar	2 bar	2 bar
3	2 bar	blank	2 bar
4	blank	blank	blank
5	blank	3 bar	blank
6	3 bar	3 bar	3 bar
7	3 bar	blank	blank
8	blank	blank	blank
9	blank	blank	blank
10	blank	white 7	white 7
11	white 7	blank	white 7
12	white 7	blank	white 7
13	white 7	blank	white 7
14	white 7	1 bar	white 7
15	white 7	1 bar	white 7
16	white 7	1 bar	white 7
17	blank	1 bar	blank
18	blank	blank	blank
19	blank	blank	blank
20	1 bar	blank	1 bar
21	1 bar	blue 7	1 bar
22	1 bar	blue 7	1 bar
23	blank	blue 7	1 bar
24	blank	blue 7	1 bar
25	blank	blue 7	blank
26	blue 7	blue 7	blank
27	blue 7	blue 7	blank
28	blue 7	blank	blue 7
29	blue 7	blank	blank
30	blue 7	blank	blank
31	blue 7	2 bar	blank
32	blank	2 bar	2 bar
33	blank	blank	2 bar
34	blank	blank	2 bar
35	2 bar	3 bar	blank
36	2 bar	3 bar	blank
37	blank	blank	3 bar
38	blank	blank	blank
39	3 bar	blank	blank
40	blank	blank	blank
41	blank	blank	blank
42	blank	red 7	blank
43	blank	red 7	red 7
44	blank	red 7	blank
45	red 7	blank	blank
46	blank	blank	blank
47	blank	blank	blank
48	blank	blank	blank
49	blank	blank	3 bar
50	blank	3 bar	3 bar
51	3 bar	3 bar	3 bar
52	3 bar	3 bar	blank
53	3 bar	blank	blank
54	blank	blank	2 bar
55	blank	2 bar	2 bar
56	2 bar	2 bar	2 bar
57	2 bar	blank	blank
58	blank	blank	blank
59	blank	1 bar	1 bar
60	1 bar	1 bar	1 bar
61	1 bar	1 bar	1 bar
62	1 bar	1 bar	1 bar
63	blank	blank	blank
64	blank	blank	blank

Red White & Blue Slot Gaming Process

After the customer clicks on the spin button, the RNG determines three numbers, and corresponding characters appear on the reels.

• For example, if you have numbers 1, 2, and 3, you will see a combination of three bars.
• If the generator gives you 5, 10, and 15, a combination of "blank," "white 7", and "white 7" lands on the reels.

As you can see from the table, some of the generated numbers produce the same symbols on the same or even different reels. Also, look at the number 45. It is the only number that allows you to get the red seven on the first reel, starting the two highest combinations in the Red White & Blue slot.

The same goes for 10 on the second reel (white 7) and twenty-eight for the third reel (blue 7). As you can see, the most valuable combination (red, white, and blue sevens) can be formed only if the RNG gives out 45, 10, and 28 in this precise order.

On some slot machines in some countries, there is a plate with data on the so-called "stop numbers" for all symbols on each reel. You can count them yourself, but we did it for you.

Weights for the Red White and Blue IGT Slot

Look at the table:

STOP NUMBER	REEL 1	REEL 2	REEL 3
Red 7	1	3	1
White 7	6	1	7
Blue 7	6	7	1
3 BAR	6	7	5
2 BAR	7	6	9
1 BAR	6	8	9
Blank	32	32	32
TOTAL	64	64	64

Red White and Blue Slot Return Rates

Here is one more helpful table:

COMBINATIONS	PAYOUTS	NUMBER	ODDS	PAYBACK
Red 7, white 7, blue 7	2400	1	0.000004	0.009155
Red 7, red 7, red 7	1199	3	0.000011	0.013721
White 7, white 7, white 7	200	42	0.000160	0.032043
Blue 7, blue 7, blue 7	150	42	0.000160	0.024033
Any 3 sevens	80	1199	0.004574	0.365906
1 bar, 2 bar, 3 bar	50	180	0.000687	0.034332
3 bar, 3 bar, 3 bar	40	210	0.000801	0.032043
2 bar, 2 bar, 2 bar	25	378	0.001442	0.036049
Any red, any white, any blue	20	113	0.000431	0.008621
1 bar, 1 bar, 1 bar	10	432	0.001648	0.016479
Any 3 bars	5	7977	0.030430	0.152149
Any 3 reds	2	335	0.001278	0.002556
Any 3 whites	2	1036	0.003952	0.007904
Any 3 blues	2	756	0.002884	0.005768
3 blanks	1	32,768	0.125000	0.125000
Other	0	216,672	0.826538	0.000000
TOTAL		262,144	1.000000	0.865761

The lower right cell shows the return of the Red White & Blue. In percentage terms, it is 86.58%. In the long run, the machine pays $86 out of every $100 total bet amount.

1. Calculations were made for one coin.
2. If you put two coins, you will get the same results.
3. But three coin wagers increase the payback to 87.47% because the two highest combinations feature increased payouts.

Summary

You should also know that the term "random number generator" is somewhat incorrect. RNGs used in slots are pseudo-random as they are based on complex algorithms. 

If you are interested in this subject matter, read more about RNGs in the gambling industry

The following articles on Casinoz will describe other aspects of slot machine mechanics and mathematics.