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

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  • jbrent95
    SBR MVP
    • 12-07-09
    • 1221

    #1
    How do I calculate the required winning percent for each leg of a parlay?
    Is there a formula?
  • mathdotcom
    SBR Posting Legend
    • 03-24-08
    • 11689

    #2
    Sports betting and handicapping forum: discuss picks, odds, and predictions for upcoming games and results on latest bets.
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    • jbrent95
      SBR MVP
      • 12-07-09
      • 1221

      #3
      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?
      Comment
      • WendysRox
        SBR High Roller
        • 07-22-10
        • 184

        #4
        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
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        • WendysRox
          SBR High Roller
          • 07-22-10
          • 184

          #5
          Originally posted by 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?
          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
          Last edited by WendysRox; 10-28-11, 07:24 PM. Reason: screwed up my math
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          • jbrent95
            SBR MVP
            • 12-07-09
            • 1221

            #6
            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 ?
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            • WendysRox
              SBR High Roller
              • 07-22-10
              • 184

              #7
              Originally posted by 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 ?

              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 .
              Comment
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