A parlay (or "multi") is a single bet that links together two or more individual wagers. The lure is obvious: small stakes can turn into massive payouts. However, the mathematical reality of parlays is that the house edge compounds just as quickly as the potential winnings.
1. The Multiplication Rule
The core of a parlay is the Multiplication Rule for independent events. To calculate the probability of a parlay winning, you multiply the individual probabilities of each "leg" occurring.
For example, if you have three independent bets, each with a 50% chance of winning (0.50):
0.50 x 0.50 x 0.50 = 0.125 or 12.5%
Even if each individual bet feels like a "coin flip," the likelihood of all three hitting is significantly lower than any single event.
2. True Odds vs. Implied Odds
In a fair world, if you bet on three coin flips, the payout would be 8.00. However, sportsbooks bake a "vig" (margin) into every price.
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Individual Leg: A 1.91 (–110) price implies a 52.38% probability.
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The Compounding Vig: When you multiply these prices together, the sportsbook’s edge multiplies too. In a 5-leg parlay, you aren't just fighting the variance of the games; you are paying the house margin five times over within a single transaction.
3. The Correlation Exception
The math changes when events are dependent or correlated.
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Negative Correlation: Betting on two opposing outcomes in the same game (e.g., Team A to win and Team B to win). The probability of both occurring is zero.
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Positive Correlation: Betting on a Quarterback to throw for 300+ yards and his Wide Receiver to have 100+ yards. If the first happens, the second is much more likely.
4. Expected Value (EV)
Most parlays have a negative Expected Value (−EV). While they are excellent for entertainment, they are statistically difficult to beat long-term because the "break-even" win rate required increases exponentially with every leg added.
To find the EV of a parlay, you use:
EV=(P(Win)×Profit)−(P(Loss)×Stake)
The Bottom Line: Parlays are high-variance instruments. The probability of success shrinks much faster than the payout grows. Most people play them, and play them poorly.
AND THIS IS WHERE WE COME IN.
Hours and hours of trawling through lines and data, heat maps, player data and all the rest to find the best positions for our customers. Most people are too busy to want to look that deeply into the game narratives to find the profit. It's what we DO. And we love it. Come and join us.
Game On. Play On.
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