Calculation of Parlay Payouts

Keywords for this page:

First off, parlay payouts are computed by simply multiplying the stake by the parlay-odds. That is,

Payout = Stake x Parlay-odds

Parlay-odds may be fixed-odds or computed-odds. Fixed-odds are values set by the sportsbook based on the number of selections in the parlay; some examples are listed in parlay types section.  There is nothing to be calculated in the case of fixed parlay-odds except the payout using the above equation.

Computed parlay-odds are calculated from the individual odds of the selection. Their computation for the different odds representations are shown below using the following parlay as an example.

Decimal odds:
   Parlay-odds = product of individual odds
                       = 3.25 x 1.50 x 1.91 x 2.40 x 1.80
                       = 40.22

US Odds:
   Parlay-odds =  products of (100/-odds + 1)  * products of (+odds/100  + 1)
                 = (225/100+1) * (100/200+1)  x  (100/110+1) * (140/100+1)  * (100/180+1)
                 =      3.25         *       1.50         *         1.91       *        2.40        *      1.80
                 = 40.22

That is, divide 100 by the negative odds and add 1; divide the positive odds by 100 and add 1. Then multiply all.

Fractional Odds:
     Parlay-odds = products of (fraction odds + 1)
                         =  ( 9/4 + 1) * (1/2 + 1)  *  (10/11 + 1) * (7/5 + 1) * (4/5 + 1)
                         =      3.25     *     1.50     *        1.91      *       2.40   * 1.80
                         = 40.22

So, whichever odds representation you use, you'll arrive at the same value of parlay-odds. And, once you have the parlay-odds, then the calculation of the payout will be straightforward. For example, for a stake of $50, the above parlay pays,

Payout = $50 x 40.22 = $2011.00

To compare single bets and parlays, let's suppose you choose to bet on each of the five choices individually as single bets and you still want to risk only the same $50, then you have to bet $10 on each selection. In this case, the first game will bring you $10X 3.25= $32.50, the second one, $10 x 1.5 = $15, the third, $10 x 1.91 = $19.10, and so on. Your total return will be a mere $108.60. Nevertheless, as long as all of the predictions are not incorrect, you'll still be getting some of your money back; though it could only be a pittance.