How do I calculate the required winning percent for each leg of a parlay?

[jbrent95]

Is there a formula?

[mathdotcom]

http://www.sbrforum.com/betting-tools/parlay-calculator/

[jbrent95]

Thanks Mathy,

For a 3 team parlay with all three teams at -110, I read that the break even win rate is 52.28%. How do I calculate that?

[WendysRox]

I made up this excel spreadsheet to help me decide which book to use for a specific teaser. I won't guarantee that my math is correct, but I thought this might help. I'm terribly hungover, but I assume it would work or parlays as well.

I use the following formula to calculate the required win percentage for the entire parlay to be advantageous.

=IF(G4<0,ABS(G4)/(ABS(G4)+100),100/(100+G4)) ...in this example, cell G4 is the odds I am getting on the play.
To get the one-game required win percentage, I use this formula:

=H5^(1/$E5) where H5 is the required probability of winning the parlay (the above formula) and $E5 is the number of teams.


edit: left out a word

[WendysRox]

Thanks Mathy,

For a 3 team parlay with all three teams at -110, I read that the break even win rate is 52.28%. How do I calculate that?

Actually, using the above method (in my previous post), I come up with required win percentage of 52.38 for a 3-teamer consisting of -110 odds and a single-game required win percentage of 80.61 ....Here's the math:

=IF(-110<0, ----which it is so---- ABS(-110)/(ABS(-110)+100) ---or---- 110/210 ----or---- .5238095

and

.5238^(1/3) = .5238^.3333 = .8061

so, the required one game win percentage is 80.61%


edit... I am really sorry, but I calculated the required win % for a 3-team teaser paying -110. Here's the math for a 3-team parlay paying +600...

100/(100+600) = 100/700 = .1428

and,

.1428^.3333 = .5227 so, yes, you are right. You'd need to a one-game win probability of 52.27% (or so) for 3-team parlay that paid 6 to 1.


Sorry for the hungover math

[jbrent95]

If I wanted to see what to determine the winning percentage for each leg to obtain at 5% ROI, is this the correct calculation:

1.05/(1+6) = .15 for a 3 team parlay ?

[WendysRox]

If I wanted to see what to determine the winning percentage for each leg to obtain at 5% ROI, is this the correct calculation:

1.05/(1+6) = .15 for a 3 team parlay ?

It seems that you just showed me something new. What you've done is basically used desired edge to calculate required win probability. In other words, if I wanted to find a 5% edge in a +600 odds play, I'd need a win percentage of roughly 15%.

The desired edge is anything over 1, as in your .05. So, if I wanted a 30% edge in this situation, I'd need a win % of 18.57%....

1.30/(1+6) [---or--- 130/(100+600)] = 1.3/7 = .1857 .......interesting!

As for the ROI. I must be too tired to figure that right now. I'm running on 6 hours of sleep and 12 hours of work after drinking for 5 hours last night .