# Buying Half Points in Football

A statement repeated on betting forums often is *“if buying
half-points were +EV the bookmaker wouldn’t sell them”*. This

is just another football betting myth. In this article I’ll discuss buying

half-points for NFL football betting in great depth, touch on

college football, and teach you easy to follow

football betting strategy for buying half-points.

## Buying Half Points Explained

Most online betting sites (Bovada being the exception) allow

bettors to purchase half-points from a point spread starting at

10-cents each. So for example, if the point spread is -6.5 -110

you can purchase a half-point bringing it to -6.0 -120, or 2

half-points bringing it to -5.5 -130. If the point spread is

+4.5 -105 you can purchase to +5.0

-115 or +5.5 -125. Now there are some exceptions to this.

For good reason

3 points is the most common margin of victory in football,

purchasing across it either costs more or is restricted.

Generally speaking it costs 25 cents for buying on or off

the 3. So +2.5 to +3.0, +3.0 to +3.5, -3.5 to -3.0 and -3.0

to -2.5, those four half point moves cost 25 cents per half

point. At some sites this is true only for NFL football, and

not college football. For

example, BetOnline charges only 15 cents for those four

mentioned buys when the league is college football.

The

majority of online betting sites now charge 15 cents for

buying on or off the 7; specifically, +6.5 to +7.0, +7.0 to

+7.5, -7.5 to -7.0 and -7.0 to -6.5. A few sites charge

more, for example Pinnacle Sports most often charges 17

cents for half-point buys involving the 7. It should be

noted this is a rather new premium. I’ve found many local

bookies in the US still sell these for 10 cents each, but

online 15 cents or greater is standard.

## The Value of Half Points

Finding the fair value of a

half-point purchase requires two things 1) a push chart and 2)

trivial mathematics. The table to the left is a push chart I

created for NFL football; I’ll discuss push charts briefly later

in this article. As far as the math goes we’ll need to first

calculate our implied probability using the formula

risk/return=implied probability, where return is stake+win. For

example: -110 is risk $110 to win $100; the return is $210 ($110

stake + $100 win). So for -110 the implied probability is

110/210=0.5238 or in other words 52.38%. This tells us at odds

-110 we need to win 52.38% of the time to break even.

Calculating the value of a half-point buy is now a matter of

simple mathematics, so long as we already have a push chart.

Considering we have one, let’s a take a look at the value of

moving a point spread from +6.5 -110 to +7.0. On the NFL push

chart I just provided you’ll see the favorite wins by 7 points

5.7% of the time. Now considering at +6.5 we lose on a -7

outcome, and now we push at -7 we’re going to take half the 5.7%

probability and add it to the 52.38% implied probability of

-110.

Why only half? If we were moving from +6.5 to +7.5 we would

take the full 5.7% value. However moving +6.5 to +7.0 we can

only take half because on that number we push not win. Our

opponent (the bookmaker) who has -7.0 also pushes. So half the

5.7% is in his -7.0 line, and half the 5.7% is in our line of

+7.0. The same would be true moving +7.0 to +7.5; we take half

the push probability of 7, because we’re going from a push on 7

to a win on 7. Our increase is half the probability. When

dealing with half points we’re always either moving off a push

(and therefore take half the probability of the number we move

off of) or onto a push (and therefore take half the probability

of the number we move on to).

So in this case of +6.5 to +7.0, half of 5.7% is 2.85%. We

add this 2.85% to the +6.5 -110 implied probability 52.38% to

get a new +7.0 implied probability of 55.23%. If you go to our

odds converter and plug 55.23% into the implied probability

field you’ll see in American odds this is -123. This tells us

moving +6.5 -110 to +7.0 is worth 13 cents. It also tells us

that +6.5 -110 and +7.0 -123 have the same expected value.

### An Important Lesson

When moving -110 to -123 the line moved 13 cents. I want to

make it clear that cents are a meaningless evaluation figure. To

best illustrate why, please allow me to exaggerate the point. We just

showed that increasing a 52.38% probability 2.85% moves the

American line 13 cents. Let’s say however the line was +6.5

-280, which is risk $280 to win $100. Using Risk $280 / Return

$380 = Implied Probability we see the implied probability of

-280 is 73.68%. If we add 2.85% to this we get a new implied

probability of 76.53. Go to our odds converter, plug in 76.53%,

and you see this is American odds -326. So the same 2.85%

increase in this case moved -280 to -326, and therefore was worth

46 cents, not 13 cents.

The lesson I’m attempting to give is the value of half points

are progressive. If the line starts at -105 the value of a half

point is less than if it started at -110; if the line starts at

-115, then it’s worth more. Likewise, when making multiple-half point

purchases each half point purchased has greater value than the

last. If betting sites didn’t limit the number of half point we

could buy at 10 cents each, we could purchase a ton of them to

the point all bets we make are +EV. I’ll come back to +EV

half-point buys in a bit, but first let me cover the best betting

sites for purchasing half points.

## Best Betting Sites for Half Point Purchases

For the most part any betting website selling half-points at

25-cents for point spreads involving +3/-3, 15-cents for point

spreads involving +7/-7 and 10 cents for all other point spreads

is ideal. However, there are small little intricacies that make

some sites more ideal than others.

BetOnline.com – While many online betting sites only allow

bettors to purchase two or three half points at 10-cents each,

BetOnline actually allows punters to purchase four. Remember the

lesson earlier, because the value of half points is progressive

each one you purchase is worth more than the last. So the fact

that they sell four for 10 cents can be a huge plus. They also only

charge 15-cents (instead of 25 cents) on college football point

spreads involving +3/-3, and also don’t charge a premium on the

+7/-7 for college football either, offering 10 cents instead of

the 15 cents many other sites charge.

JustBet.com – Although not as ideal as BetOnline, JustBet is

decent for half point purchases. Here you can purchase

3-half-points maximum at 10 cents each, and they charge just 20

cents for the three on college football.

TopBet.com – Topbet ranks #1 on our list of

sports betting bonuses, but when it comes to half point buys

here you’ll want to stick to only purchasing a maximum of 2

half-points or buying 5 or 6. This is because at TopBet the first

two cost 10 cents each and the remainder cost 15 cents each.

This makes buying 3 or 4 poor value, but buying 5 or 6 will

often offset the loss in value.

5Dimes.com – 5Dimes is the nuts when it comes to half point

buys. This is because they price half points unique depending on

which point spread you’re crossing. They also allow bettors to

purchase them unmatched in the industry 10-20 half-points per

game. They are a reduced juice sportsbook, and you’ll

quite often find the best value here.

I should note that while we love them for their great odds on

football teasers, Bovada.lv isn’t a good site for buying

half points. This is because very rarely do they even offer the

option, and when they do it’s only on low value numbers such as

buying +8.5 in NFL to +9. If you use them for other reasons,

just avoid their half point buys.

## Buying Half Point Strategy

I’ve already covered how buying half-point works and how to

calculate their value, but I haven’t discussed push charts. It’s

worth noting that season to season NFL push charts don’t change very

much and mine was last calculated going into the 2012/13 season,

so it should be good for at least a few years. When dealing with

college football you have two options #1 create a push chart, or

#2 remove vig from Pinnacle Sports.

For this you’re going to

need a massive amount of historical data. One option to obtain

this is by purchasing access to ATSdatabase.com for $49.00 for one

month or $99.00 for a year. I personally don’t find their

service worth much and some of their data needs cleansing so

paying $49.00 for one-month, followed by ripping all the data and

putting it into your own excel spread sheets is probably best.

From here what you’ll need to do is find all similar games

(paying attention to their over/under betting total as well as point spread), and then

see how often they won by the related numbers. So, you might

make push charts for totals under 44, totals 44.5 to 55.5, and

totals over 56. From here you can take all points spreads +1.5 to -1.5

of the number you’re looking to calculate for, and see how often

they won by that number.

This is a far better

option. If you’re from the US just register a fake account at

pinnaclesports.com, because they don’t accept US bettors; having

an account gives you access to their dynamic lines. At Pinnacle

the option to both buy points and sell points is available, and

Pinnacle is a very sharp reduced juice betting site. Here you

can change the point spread to any increment and then use the

remove vig calculator contained in the lower section of my

article on

handicapping the betting market. So for example, on a

betting line of -7 we first calculate their no vig -7/+7 price.

We then calculate their no vig price on +6.5 and -6.5, and then

on +7.5/-7.5. Here we can note the changes of what they’re willing

to let us buy and sell points at to see how much chance they’re

giving the seven pushing.

## Proof Buying Half Points Can be +EV

Let’s take case of a point spread that’s +9.5 -110. As

already covered earlier in this article the implied probability

of -110 is 52.38%. I also provided a push chart that showed

-10/+10 pushes about 4.9% of the time. If we decided to purchase

two half points bringing the line to +10.5, our implied

probability is 52.38%+4.9%=57.28%. If we plug this new

percentage into our

odds converter we see in American odds format this is -134.

If the bookmaker was charging the fair price for +9.5 to +10.5

he’d charge us -134, yet every betting site I know of sells

half points moving from +9.5 to +10.5 which costs just -130. If we

already thought +9.5 -110 was a neutral or better value bet,

we’d be foolish not to purchase two-half points here because doing

so lowers the bookmaker’s advantage.

Now considering 14 also has a 4.9% probability we can now

determine the following 4-half point buys are always must

purchases.

- When betting +9.5 -110 always buy to +10.5 -130
- When betting -10.5 -110 always buy to -9.5 -130
- When betting +13.5 -110 always buy to +14.5 -130
- When betting -14.5 -110 always buy to -13.5 -130

Although these are the best half point buys there are others.

Let’s take the example of a point spread +6 -115. The implied

probability of -115 is 53.49%. If we were to buy this to +7.5 we

would take half the probability of 6 which is 3.4%/2=1.7% and

the full probability of 7 which is 5.7%. So, 53.49%+1.7%+5.7%=

60.89%. Using our odds converter we can see that 60.89% is -155.6 in American

odds format. At betting sites the move +6.0 to +6.5 would cost

10 cents where the next two cost 15 cents each, because they

involve the seven. So, 110+10+15+15=150; the betting site is

giving us -150 when we just calculate the fair price for the

extra points should have been -155.6.

To conclude, let me mention there’s still vig in the initial

lines of all these examples. However, in these spots buying half

points did lower the bookmaker advantage. If the lines was

already a +EV bet we made it better. Perhaps if it was slightly

-EV and we were on the fence we could make it +EV with the half

point purchase. The reason these numbers work is because I’m

dealing with common margins of victory and also purchasing

multiple half points (which remember each one you purchase has a

higher value than the last). You’ll want to avoid low value

numbers. When it comes to half-point buying, our target numbers

of 7, 10, 14, 17, and 21. If we can use multiple half points to

cross these numbers more times than not we’re increasing the

value of our wager.

This concludes my article on buying half-points in football.

If you’ve read this article in full, understand it, and are

interested in buying half points for value I suggest also

reading the following articles: