Sports Betting

Last Update: Oct 27, 2011

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Sports books have to cram a lot of information on a limited amount of space. To save space they generally just throw up the numbers and you are supposed to know what they mean. The following picture is from a typical Las Vegas sports book.

Consider the first game in the upper left, which looks something like the following.

• The -10 is the point spread. This is for use in point spread bets.
• The 41 is the total. This is for use in total bets.
• The +400 and -600 are money lines. These are for use in money line bets.

Unlike horse racing bets the winner of a sports bet always gets his original bet back if he wins.

I admit "point spread bet" is not a common term in sports betting, but I'm trying to change that. What I call a point spread bet is a basic bet against the point spread. Many people call this a "straight bet" but this term can also be used, and is printed on tickets for, money liney bets, total bets, and any other bet involving just one game. So I invite the rest of the world to adopt this term.

In the example above, the Vikings are favored to win by 10 points. So two Point Spread Bets would be available on this game: (1) that the Vikings will win by 11 or more points, and (2) the Rams win or lose by 9 or fewer points. If the Vikings won by exactly 10, then Point Spread bets on both sides would push. Generally the point spread is next to the favored team and is thus a negative number.

Usually with a Point Spread Bet the bettor must risk $11 to win $10, or any proportion therein. In almost all sports bets (excluding some parlay and teaser cards) the winner gets his original bet back. For example, if you bet $110 on a Point Spread bet, and won, when you redeemed your ticket you would receive $210.

Total Bets are similar to point spread bets, except the bettor bets on the total points scored. In the example above the bettor bets whether the total points combined between the Vikings and Rams will be over or under 41. Like point spread bets the bettor must generally risk $11 to win $10, for a house edge of 4.54%.

Money Line bets are simply on whom will win straight up. In the example above, the +400 for the Rams means that a $100 bet on the Rams would win $400, or any proportion therein, if the Rams win the game. The point spread on the Vikings is -600, which means that the bettor must risk $600 to win $100.

The Parlay is a way to bet on multiple sporting events with hope for a big payoff if all of them win. With parlay cards, all picks are relative to the point spread. If just one event doesn't win or draw then you lose the entire bet. If one or more event is a draw then those events are ignored. If you win all the other events you get paid according to the number of events that you did win. In the event all games bet on result in a push except one or none then the entire bet becomes a push. The following table shows the house edge for various number of picks and pays assuming a random picker.

Parlay bets can be done "against the board" or "against the card." Against the board the bettor goes up to the window and states his picks and the point spread on the board is used. Against the card the bettor fills out a 4.25" by 11" colored card with his picks against the point spreads stated on the card. For the recreational gambler if you must make a parlay bet I recommend going off the board. However parlay cards can be exploited to a degree by picking events in which the line on the board has moved in your favor relative to the card, especially against the critical 3 and 7 point margins of victory in football.

Parlay Bet House Edge
Pick	Pays	House Edge
2	2.5	12.50%
2	2.6	10.00%
2	2.7	7.50%
2	2.8	5.00%
2	2.9	2.50%
3	5	25.00%
3	6	12.50%
3	6.5	6.25%
4	10	31.25%
4	11	25.00%
4	12	18.75%
4	13	12.50%
4	14	6.25%
5	25	18.75%
5	26	15.63%
5	30	3.13%
6	30	51.56%
6	35	43.75%
6	40	35.94%
6	45	28.13%
6	47	25.00%
6	50	20.31%
6	55	12.50%
6	60	4.69%
7	92	27.34%
8	180	29.30%
20	200,000	80.93%

The general formula for the house edge for a random picker is 1-(w+1)/tⁿ, where w is the winning odds on a "to one" basis, and t is the number of teams. For example, if a 3-team parlay pays 6 to 1, then the house edge is 1-(6+1)/2³ = 1-(7/8) = 1/8 = 12.5%.

My Vegas sports book comparison shows the parlay odds at all the Vegas sports book groups.

If you mix just one event into a parlay that does not pay -110, then a calculation is made to determine the payoff odds. The calculation is made as if every bet were made independently. For example, if you made a three team parlay with odds of each event of -110, +200, and -300, then the payoff odds would be (21/11) × (3/1) × (4/3) = 7.6364 for 1, or 6.6364 to 1. If you used this method of calculation in making all -110 bets, then your payoff odds would be better, except for a 3-event parlay. The following table shows the house edge under MGM-Mirage parlay and the calculation method.

A nice trick to get out of the stingy off the board pay table on parlays is to mix in any event that does not pay -110. For example, if player X makes an 8-team parlay at an MGM-Mirage sports book, all at -110, he stands to be paid 150 to 1. If player Y makes an 8-team parlay, with 7 picks at -110, and one at -120, he will be paid (21/11)⁷×(22/12) – 1 = 168.4446 to 1. So, player Y substitutes a game that is more likely to win, and stands to get paid significantly more. If there are no sides that pay anything other than -110, then consider mixing in a money line bet.

Teasers are similar to parlays except the point spread on each game moves a certain number of points in the player's favor. In football the player gets 6 to 7 points, and in basketball, 4 to 5 points. The player pays for this in the form of much lower winnings. For example, if the Vikings were part of a 6-point teaser, then they would only need to win by more than 4 points to cover. If the Rams were part of a teaser, they could win, or lose by less than 16, and cover.

For more information on NFL teasers, please see my section on betting the NFL.

My Vegas sports book comparison shows the teaser odds at all the Vegas sports book groups.

In football and baskbetball, the straight bet player has the option to move the point spread 1/2 point to his advantage. The cost of this half point is laying 120, as opposed to 110. Not all sports books allow this, and if they do, they usually don't let you buy off of the common three-point margin of victory in football.

Futures are a bet on who will win the championship when there are still more than two possible teams to bet on. The house edge on futures varies substantially from one sportbook to another. However in general they are a sucker bet and to be avoided. For information on who does offer the best futures in Las Vegas visit my sports betting appendix 5.

• Betting the NFL In-depth look at betting professional football.
• Betting the MLB In-depth look at betting professional baseball.
• Betting the NBA In-depth look at betting professional basketball.
• Appendix 1 Comparative study on who has the best lines in Vegas.
• Appendix 2 Various topics in sports betting.
• Appendix 3 List of Las Vegas sports book families.
• Appendix 4 Fair prices to buy and sell points in the NFL.
• Appendix 5 Explores sports futures in greater depth.
• Appendix 6 Lost and expired tickets.
• Appendix 7 Companion to appendix 1, showing NFL money line pairs from several Internet sportbooks.
• Appendix 8 Comparative study on who has the best lines offshore.
• Appendix 9 Companion to appendix 8, showing NFL money line pairs from offshore sportbooks.
• Appendix 10 NFL teasers.
• Appendix 11 College football money lines.
• Total number of kickoffs in Super Bowl 43. Were there 9 or 10?
• Vegas sports book comparison at WizardOfVegas.com. Who offers what odds on parlays and teasers, as well as rebate percentages.

For a simplified explanation of sports betting, please visit my companion site Wizard of Vegas .