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Slot Machine Odds in Las Vegas


The following table ranks the Las Vegas casinos according to the looseness of their video display reeled nickel slot machines. The returns are based on a sampling of five different types of machines. The data collected goes back as far as October 2001 so the information is a bit dated.

Las Vegas 5 Cent Slot Survey

Rank Casino Average
1 Palms 93.42%
2 Gold Coast 92.84%
3 Sahara 92.81%
4 (tie) Bourbon Street 92.63%
4 (tie) Imperial Palace 92.63%
4 (tie) Slots a Fun 92.63%
7 Key Largo 92.60%
8 Western 92.57%
9 Ellis Island 92.56%
10 El Cortez 92.56%
11 Orleans 92.56%
12 Circus Circus 92.56%
13 Gold Spike 92.55%
14 Fitzgeralds 92.54%
15 Fiesta - Rancho 92.53%
16 Arizona Charlie's East 92.51%
17 Barbary Coast 92.50%
18 Terrible's 92.49%
19 Arizona Charlie's 92.49%
20 Hard Rock 92.47%
21 Town Hall 92.47%
22 Longhorn 92.47%
23 Riviera 92.23%
24 California 92.14%
25 Lady Luck 92.10%
26 Nevada Palace 92.06%
27 Plaza 91.94%
28 Luxor 91.92%
29 Paris 91.92%
30 San Remo 91.88%
31 Excalibur 91.84%
32 Palace Station 91.84%
33 Ballys 91.82%
34 Las Vegas Club 91.76%
35 Four Queens 91.75%
36 Texas Station 91.71%
37 Casino Royale 91.67%
38 Boulder Station 91.55%
39 Aladdin 91.5%
40 O'sheas 91.48%
41 Hilton 91.40%
42 Boardwalk 91.28%
43 New York New York 90.99%
44 Horseshoe 90.96%
45 Sam's Town 90.89%
46 Santa Fe Station 90.87%
47 Flamingo 90.86%
48 Golden Nugget 90.85%
49 Stratosphere 90.8%
50 Tropicana 90.71%
51 Golden Gate 90.64%
52 Silverton 90.57%
53 Main Street Station 90.56%
54 Westward Ho 90.40%
55 Fremont 90.37%
56 Castaways 90.36%
57 Monte Carlo 90.24%
58 Stardust 89.97%
59 Frontier 89.91%
60 MGM Grand 89.81%
61 Harrahs 89.32%
62 Treasure Island 89.32%
63 Mirage 89.3%
64 Caesars Palace 89.05%
65 Mandalay Bay 88.87%
66 Rio 88.72%
67 La Bayou 88.26%
68 Mermaids 88.26%
69 Bellagio 87.42%
70 Venetian 86.66%
71 Airport 85.02%

Excluded Casinos

The Suncoast and Rampart Casino in Summerlin do not allow playing slots and taking notes at the same time. I can not include any casino that prohibits the method in which I gather data.

Location Averages

The next table shows the average return by location.

Returns by Region

Location Average
Off strip 92.07%
Downtown 91.66%
Strip 91.47%
Total 91.74%

The above sign can be found across the street from the Palms. Although I did the study Anthony Curtis published it in the LasVegas Advisor, which is how it become well known. The"..." in the sign encompases quite a bit of information,which was conveniently left off the sign. Actually the study only says that the Palms had the lowest nickel video slotsof the casinos surveyed in Las Vegas. The small print at thebottom says, "Independent study conducted between November2001-February 2002 on Austin Powers, Fortune Cookie, Reel'em In, and Wheel of Fortune games. They left off LeopardSpots, and the study began in October.


There seemed to be no truth behind slot placement myths. Machines on the end of a bank did no better on average than those in the middle. There was also no correlation between return and proximity to such things as the main door, table game pit, high traffic areas, and low traffic areas.

Most casinos were very consistent in their slot returns.If one nickel machine had a return of x% then all others like it also returned x%. However some casinos did mix up loose and tight machines, most notably Treasure Island and the California casinos.


A kind and anonymous source provided me with par sheets for the games in question. The EPROM (Erasable Programmable Read Only Memory) chip is what tells the machine the order of the symbols on the reel, in some cases how the stops are weighted, how much each winning combination pays, and any other pertinent information about how much the machine pays.It is up to the slot manager to select which EPROM chip to order according to the return percentage desired. On atypical game there might be about 8 different possible return percentages, ranging from about 85% to 98%.

Each of the different par sheets has five sets of distinct reels. On video display slots the stops are not weighted; in other words all stops are equally likely. The distribution of each symbol on each reel is what determines the theoretical return of the machine. For example a higher paying machine may have more of the higher paying symbols.

On the machine itself three consecutive symbols arevisible on five different reels. By comparing actualobservations of results to the par sheets it is possible todetermine which reels the machine uses, and thus which par sheet and which return. There are various three-symbol combinations that appear in at least one but not all par sheets. So if one of these combinations occurs on an actualmachine it narrows down the possible par sheets. By playingenough the player can narrow down the possible par sheets tojust one.

To help identify the unique combinations I wrote a computer program for each game, which had the exact reel order of all 5 reels of all the par sheets. The program then counted the number of par sheets with each possible three-symbol combination. If the number was greater than 0 and less than the maximum then that combination was identified along with the associated par sheets it belonged to.

It is then a matter of simply playing the game and comparing the outcomes to the list of partially unique combinations. It only takes about 5-10 plays per machine to narrow down the possibilities to just one par sheet.

The averages in the table are actually an average of averages. For each kind of machine at each casino I took an average return. Then I took the average of these averages over the five kinds of machines I tested for.

Slot Machine Definition


There is some confusion about what constitutes a "slot machine" or "slot." My definition, and that of most gamblers, is a gambling machine with either actual spinning reels or video representations of the them.

People in the gaming business and regulators generally refer to a slot machine as any gambling machine, including reeled slots, video poker, video keno, video blackjack,etc.. For purposes of statistics both casino managers and regulators combine all the electronic gambling machines together. For example, the Slot Chart in Casino Player magazine and reports by the Nevada Gaming Control Board do not isolate just reeled slots but consider all electronic games a "slot." Therefore my return percentages should not be expected to agree with those reported by the casinos or regulators. As far as I know mine is the only source to isolate just the return of reeled slots.


I would like to thank Rob Feldheim for helping with the slot play and record keeping. Rob helped me with most of the casinos on the east side of town and part of downtown. I would also like to thank par Sheet Pete (not his real name)for providing the par sheets, without which this project would not have been possible.

Internal Links

Go to slot machine appendix3B (Jean/Primm slot returns).
Go to slot machine appendix 3D(Henderson slot returns).
Go to slot machine appendix 3E(Las Vegas quarter and dollar slot returns).
Go to slot machine appendix 3F(Montreal slot return).
Go back to slot machines.

External Links

The main-stream media has covered this study in depth. Here are links to some articles.

  • Turning'em loose, an article that appeared in the Las VegasReview Journal on May 19, 2002, about the possible effectsof this study.
  • One-Armed Bandit or Robin Hood?, an article by myself for Contingencies Magazine explaining the methodology, results, and weaknesses of the study.
  • Play by the rules and the one-armed bandits will still win. Boston Globe article about slot machines, in which my Las Vegas survey is mentioned and my advice quoted. (cache)