When it comes to “buying half-points in football” the internet is full of unhelpful advice. In fact one website with strategy in their domain, currently listed #3 in Google for the topic has a 576 word article that doesn’t tell the reader much and concludes with “For the most part, buying points in modern sports betting isn’t a profitable enterprise.” Considering I fully disagree with that statement, let me take some time to cover this topic.
Buying Points Explained
For the topic I’m about to discuss the exact rules and logistics vary between betting sites. To keep things simple I’ll use rules and policies of Bookmaker (www.bmaker.ag) to illustrate how buying half points works. At Bookmaker the first three half points cost 10 cents each, and from fourth half-point on they cost 20 cents. For example, if the line is New England Patriots -6.5 -110 a punter can purchase a single half-point or multiple half-points, thus having the option to bet the Patriots at -6 -120, -5.5 -130, -5 -140, -4.5 -160, or -4.0 -180.
The exception is the following four scenarios cost 25 cents per half-point:
- +2.5 to +3.0
- +3.0 to +3.5
- -3.5 to -3.0
- -3.0 to -2.5
The reason I chose Bookmaker (www.bmaker.ag) for the example is because they have by far the fewest number of exception; here all point spreads except those involving a three, are sold at 10 cents. Other online betting sites charge 15-20 cents for the 7 and sometimes 15 cents for the 10 and 14 as well. This is not the case at Bookmaker, where all those cost ten cents.
Calculating the Value of a Half Point Purchase
In order to calculate the value of a half point we need to know how often teams will push on the point spreads involved; in other words: we need a push chart. This is a topic I covered in detail in the intensegambling.com article on teaser betting. To keep things simple let’s use the push chart mikevegas posted at roughingthepunter.com here (http://www.roughingthepunter.com/showthread.php?t=1907). Let me go ahead and show some examples.
The point spread is -6.5 -110 and we want to know if purchasing it down to -6 -120 is better play. Well the first step is to go to our odds converter and calculate:
- -110 requires a 52.4% win rate to break even
- -120 requires a 54.5% win rate to break even
When we examine the two we see the difference is 2.1%. So what we need know now is if moving from -6.5 to -6.0 gives us a more than 2.1% increased win probability, if it does then we’re going to bet -6.0 -120, if it does not we’ll stick to -6.5 -110.
Our next step is to refer to the push chart linked earlier and discover the odds of a push on -6 are 3.4%. However we can’t take full credit for that because on 6 we push (not win), our opponent also pushes… so, half of that 3.4% probability is built into their line of +6 and half is built into our line of -6. This means our odds of winning when moving from -6.5 to -6 are increased by half of 3.4% which is 1.7%.
If you’re following you should understand that we’re going to stick with -6.5 -110 because -6.0 -120 doesn’t increase our win rate by the 2.1% we would have needed it to; at 1.7% it falls 0.4% short.
Half Point Buying Cheat Sheet
When moving from -110 to -120 all we need to do is find numbers where the push probability is 4.2% or higher. According to the push chart we linked to earlier, we find 7, 10, 14, and 17 meet that criteria. As a result, there are 16 scenarios where if about to bet the point-spread you should for certain purchase one or two half-points.
- +6.5 -110 = always purchase to +7.5 -130
- +7.0 -110 = always purchase to +7.5 -120
- +9.5 -110 = always purchase to +10.5 -130
- +10.0 -110 = always purchase to +10.5 -120
- +13.5 -110 = always purchase to +14.5 -130
- +14.0 -110 = always purchase to +14.5 -120
- +16.5 -110 = always purchase to +17.5 -130
- +17.0 -110 = always purchase to +17.5 -120
- -7.5 -110 = always purchase to -6.5 -130
- -7.0 -110 = always purchase to -6.5 -120
- -10.5 -110 = always purchase to -9.5 -130
- -10.0 -110 = always purchase to -9.5 -120
- -14.5 -110 = always purchase to -13.5 -130
- +14.0 -110 = always purchase to -13.5 -120
- -17.5 -110 = always purchase to -16.5 -130
- -17.0 -110 = always purchase to -16.5 -120
To get back to the statement of the article we’re writing rebuttal to “For the most part, buying points in modern sports betting isn’t a profitable enterprise.” In the 2010-2011 season 22.3% of the closing lines involved a point spread where one or both sides fit into the 16 subsets above. When examining it with all options, counting two options (team A or Team B) for each game, of all options 17.47% of the time a bet fell into one of these two subsets. So what this article failed to tell you is that 17.47% of the time on average you’d be moving the odds from the bookmaker’s favor to your own favor by purchasing half-points.
There are two potential issues here:
- Many online betting sites restrict or charge more for half-point purchased on or off the 7. When betting a www.bookmaker.com this isn’t an issue.
- Don’t ever trust someone else’s push chart. Be sure to read my teaser betting article where I discuss data sources and how to create your own push charts.
Other than these two issues, at most betting sites 17.47% of the time it is optimal strategy to purchase the half point.
Advanced Buying Points Strategy
If you want to get even more creative read and understand my article on purchasing half points in basketball. In that particular article you’ll learn that when half points are strung together the value changes. To give you a quick clue, when moving from -110 to -140 we calculate as follows. -110 has a 52.4% required break even and -140 has a 58.3% break even. The difference is 5.9%. Remember in our earlier example we needed one half point to be worth 2.1%. Well here 5.9/3=1.966%. The higher the starting price is, the less you need the half point to increase the win probability by.
The final reminder is when using a push chart you always use half of the percentage per half point. This is because with every half point you’re always moving either on a push, or off of a push. For example -6.5 to -6.00 you’re moving onto a push and the opposing line (+6.0) has half the push probability as well. Take -7.00 to -6.5 well in this case you’re coming off a push and the number you came off of also had half the push probability assigned to the opposing team’s line. To restate this with an example if you’re at +10.0 and moving to +10.5 you look at the probability of 10 point loss and then cut that probability in half.