A parlay combines multiple bets into one wager — and the payout math is more brutal than most bettors realize.
Parlays are one of the most popular bet types in sports betting, but surprisingly few bettors understand exactly how the payout is calculated. Getting this right is essential for knowing when a parlay offers any real value.
The Basic Parlay Math
Each leg of a parlay is converted to its decimal odds equivalent, then multiplied together. For example, a two-team parlay with both sides at -110 works like this:
- -110 converts to 1.909 in decimal odds
- 1.909 × 1.909 = 3.645
- Subtract your $1 stake: net profit of $2.645 per $1 wagered
A $100 two-team parlay at -110/-110 pays out roughly $264 total ($164 profit). Sportsbooks typically list this as paying "2.6 to 1."
Where the House Edge Hides
The true fair payout for a two-team parlay (if both sides were -100, i.e., no vig) would be 3.0x. But because each leg is -110, the sportsbook shaves approximately 4.5% off the top. On a three-team parlay, that edge compounds to over 12%. The more legs you add, the wider the gap between what you're paid and what a fair market would offer.
This is why parlays are high-variance, not high-value. The odds are stacked against you from the moment you add a second leg.
Correlated vs. Independent Legs
Standard parlays assume each leg is statistically independent. Sportsbooks prohibit true correlated parlays (e.g., same-team moneyline + spread) precisely because correlated outcomes reduce the house edge. Understanding which combinations sportsbooks allow — and why — gives you a clearer picture of where the math sits.
Using a Parlay Calculator
Rather than doing the decimal conversion manually, use a parlay calculator to model exact payouts. Tools like Oddible let you input legs with their exact odds, see the true implied probability, and compare the offered payout against the mathematically fair return.
Track your parlays and calculate true payouts with Oddible →
