A teaser is a type of accumulator bet, meaning that the results of several individual bets are cumulative.  The difference between a teaser and a parlay bet is that teaser bets are always on a spread or total bet, and the bettor is given a fixed number of points to add to every leg to move the odds of winning in the favor of the bettor.  Common numbers of points added to each leg are 6, 6.5 or 7 for NFL games, and 4, 4.5 or 5 for NBA games.  The higher the points awarded, the lower the payout for winning. 

Teaser rules and payout structures change from sportsbook to sportsbook.   Some books allow teasers with as few as 2 teams, some require a minimum of 3.  Some books set a maximum on the number of bets that can be teased, others do not.  All books increase the payout based on the number of teams that are teased - more teams equals more payout is you win.  Profiting to the maximum extent possible requires the bettor to understand how to compare the value of the payouts for different teaser odds.

Let's look at a common payout structure for 2-, 3- and 4-team teasers:

Comparing Teaser Odds:

Which, if any, of the teaser bets in the above table provide the best value? We will have to dissect them to know.  Let's look first at the win percentages we would need to break even on each:

Note that I stated the probabilities as percentages, which tend to be easier to conceptualize. Mathematically, we could just look at .5238, .3571 and .2500. 

If we assume that the minimum odds to win each leg are equal, then to solve for the minimum leg probabilities for 2-, 3- and 4-team teasers is handled thus:

What this shows us is that the minimum probability required to win the individual legs of a teaser bet in the payout structure we are exhibiting actually decreases substantially from 2-team to 3-team, with an additional slight decrease from 3-team to 4-team.  Bottom line being that (assuming your individual bet advantages will average out over time) you would be getting significantly better value playing 3-team teasers over 2-team teasers, and slightly better value using the 4-team over 3-team.  Again, this is within the payout structure of the example.

Sportsbook Teaser Analysis Application

The methodology used here to show the relative values of the teaser bets described can be used to compare other teaser payout structures as well.  Sports bettors are highly encouraged to use this method and to use it to extractt he maximum value for their bets.