Converting Betting Odds To Probability - It will help You Beat The Bookies

nors
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Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby nors » Mon Dec 12, 2016 4:01 pm

I was looking at some blogs and came across this from Bitmoretechnical https://www.olbg.com/blogs/post.php?id=409333 and this from man o bong https://www.olbg.com/blogs/post.php?id=403646.

I thought it would good if a member could explain their % calculation process on the forum for different odds formats, so we could have a reference point for this on the forum.

Image Image Image

Also how do members use these percentage calculations in their day to betting, please give us some insight, especially from a football point of view and maybe from an in play point of view.

These percentage calculations may show what the bookies are getting away with in play!!

We need your betting expertise to help others on the forum.

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Re: Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby The Executioner » Tue Dec 13, 2016 7:12 pm

When I started in the betting industry many moons ago ( 1980 ) a work colleague told me the most simplest way to work the odds %% out , '' just remember what the returns would be to a one unit bet '' ...... EG 1.00 @13/8 returns 2.625 , you then divide 100 by 2.625 which gives you 38.095 and that is your percentage.

If you have difficulty remembering the returns initially - again using the example of 13/8 just add the two figures together = 21 and then divide by the 8 = 2.625

9/4 is 9+4=13 then divide by the 4 = 3.25 , 100 divided by 3.25 = 30.769 and that would be your percentage for those odds


When you have used this formula for all the odds in an event then that would give you the over-round

The same format can be used for whatever sports you may be betting on.

Here is a link to a blog that I did earlier in the year which goes in to the subject in more detail.
https://www.olbg.com/blogs/post.php?id=410963
2017 , 50x3yos To Follow ( Part 1 )
https://www.olbg.com/blogs/post.php?id=412109

2017, 50x3yos To Follow ( Part 2 )
https://www.olbg.com/blogs/post.php?id=412111

2017, 20x2yos To Follow
https://www.olbg.com/blogs/post.php?id=412443

nors
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Re: Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby nors » Wed Dec 14, 2016 9:36 am

Thanks Ex, that will help a lot.
13/8 just add the two figures together = 21 and then divide by the 8 = 2.625
11/4 just add the two figures together = 15 and then divide by 4 = 3.75. 100 divided by 3.75 =26.66%

7/2 Just add the two figures together = 9 and then divide by the 2 = 4.5. 100 divided by 4.5 =22.22 %

You then need to work out whether your bet has a better chance than its percentage chance offered by the bookies,

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Re: Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby mathsbet » Wed Dec 14, 2016 5:53 pm

There is an easier way to get straight to the probability percentage: with odds of 11/4 for example, add 11+4=15, then divide 4 by 15, which gives 0.2666 recurring, or 26.7%.

To visualise this, I would think of odds of 11/4 as saying that for every 11 times event A happens, Event B will happen 4 times, so in every 15 events, you will have 11 going one way and 4 going the other. Then your probability of the event priced at 11/4 is 4 times in 15, or 26.7%

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Re: Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby nors » Wed Dec 14, 2016 6:53 pm

Thanks mathsbet, are there any other calculations that members can pass on to other members?

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Re: Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby nors » Mon Dec 19, 2016 9:28 am

If you take a race meeting or a league and compare the % it is useful, it shows where the bookies are struggling to separate contestants. You can then compare the % between different bookies and see what they are thinking and who has made a rick.

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Re: Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby nors » Thu Jan 26, 2017 3:35 pm

When members are looking at matches or races use these calculations and you will be amazed at the clearer view it gives you.

If you compare say 2 similar races (same number of runners) or 2 like for like matches Newcastle v Reading, Brighton v Fulham you can then compare and contrast the odds - the implied probability can help you separate your best value bet from 1 you were slightly unsure about.

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Re: Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby nors » Wed Feb 01, 2017 9:59 am

In horse racing if you add 1% to each runner and then see how far each race percentage is above that 1% a runner then it can assist you when comparing races.

So a 10 runner race should be on my calculations 110%
So a 14 runner race should be on my calculations 114%

In truth it will be more like this
10 runner race 120%
14 runner race 129%

When you get races with the same number of runners it can be a good exercise to compare and contrast. You may have 1 10 runner race at 115% and another on the same card at 125%. This gives an indication of the competitive nature of the race and the bookies thinking.

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Re: Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby mathsbet » Wed Feb 01, 2017 11:41 am

Nors, I know you're probably talking about adding percentages just to see how it compares to the market, but I would stress that the objective of pricing your own events, whether races or matches or whatever else, is to find a true advantage on some outcomes. Therefore, it is imperative that you price up the event to 100%, adding no over-round, and aiming to reflect as close an approximation of the actual probability as possible.

You can then compare your 100% book prices to the 105%+ markets and you will see which prices, if any, represent true value. If you price up a book to 105% or 110%, you are adding the over-round into the calculations, which is a mistake, since the over-round only exists in bookie's profit margins, it doesn't exist in the real world, so if you give a horse a 22% probability to factor in the over-round, you are still talking about a horse with a 20% probability in the real world, where the book is always at 100%.

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Re: Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby nors » Wed Feb 01, 2017 12:19 pm

Hi Mathsbet, i was really comparing and contrasting but as you say there is no reason why you shouldn't do your own tissue

Your own 100% Tissue
The Tissue added with 1% per runner
The Actual Tissue from diff bookies.

That should make prices even clearer and should imo help RACE selection.

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Re: Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby nors » Fri Feb 17, 2017 5:33 pm

Would be good to get some examples of probability this weekend where you think the bookies have it wrong and a firms odds are just wrong.

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Re: Converting Betting Odds To Probability - It will help You Beat The Bookies

Postby nors » Wed May 17, 2017 11:45 am

Every member who wants to take their betting to another level should undertake these probability studys, it will really help you focus and help you decide on what bets to make.

There are only a few games tonight these are the best odds from a range of bookies on the Sheff Wed v Huddersfield match.

ODDS
2.60 38.46%
3.60 27.78%
3.20 31.25%

The Percentage is less than 100% it actually = 97.49%

If you can make 2.5% on every game you will be laughing all the way to the bank. Now if some of the prices are exchange prices you have to take into consideration commission but when the match goes in play you should be able to adjust. That is why its important to take the best prices as always.

We need to be doing these kind of % analisys on events and like the bookies make it a pillar of our betting.

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