Parlay Calculator
Calculate your parlay payout — then see exactly how much vig is compounding across your legs with the "Parlay Tax" analysis.
Try a quick example to see the compound tax in action.
The 4-Leg Spread Parlay at -110
Consider a hypothetical 4-leg NFL spread parlay, each leg at -110. The sportsbook shows combined odds of roughly +1228 and a $50 wager pays $664. The payout looks attractive — but the margin math tells a different story.
Each leg carries ~4.5% margin individually. In a parlay, margin doesn't add linearly — it compounds multiplicatively. By the fourth leg, the effective margin has grown to roughly 17%. A hypothetical fair payout (with no margin on any leg) would be about $800. The $136 difference represents the cumulative cost of compounding margin across four legs.
This compounding dynamic is one reason many experienced bettors note that parlays carry higher effective margin than equivalent straight bets. The mathematical efficiency depends on whether each leg independently represents favorable pricing.
How are parlay payouts actually calculated?
A parlay chains multiple bets into one all-or-nothing wager. The sportsbook converts your American odds to decimal format, multiplies them together, and then multiplies that total by your stake. For example, two legs at -110 (1.91 decimal) becomes 1.91 × 1.91 = 3.65. Your payout is 3.65× your stake, but the catch is that every leg must win for you to collect. If even one leg loses, you lose the entire bet.
What is the "Parlay Tax" and how does it compound?
Most bettors don't realize that vig compounds exponentially in a parlay. When four bets with a ~4.5% house edge each are combined into one ticket, the margin applies to every single leg. If a single bet has a 95.5% payout efficiency (4.5% vig), a 4-leg parlay has a theoretical payout efficiency of roughly 0.955⁴ ≈ 83.3%. That represents an effective 16.7% margin before any games are played. This calculator illustrates the exact compound margin for any combination of odds.
What happens if one leg of a parlay pushes?
If a leg results in a push (tie), most sportsbooks remove that leg and recalculate. A 4-team parlay with one push becomes a 3-team parlay. A 2-team parlay with a push becomes a straight bet on the remaining leg. Your potential payout decreases accordingly. The exact rules vary slightly by sportsbook, so check your platform's terms.
Are parlays a sucker bet?
It depends on context. For recreational bettors, parlays are entertainment — a small stake for a potentially large payout. The math isn't favorable, but neither is a movie ticket. For serious bettors, the answer is more nuanced: if every leg of your parlay is independently +EV (positive expected value), a parlay can actually be more capital-efficient than straight bets. The problem is that most parlays include at least one leg that isn't +EV, and the compounding vig makes the overall proposition worse than betting each game separately.
How do parlays compare to straight bets mathematically?
Straight bets generally carry lower effective margin. A straight bet at -110 carries about 4.5% vig. The same four games combined in a parlay carry roughly 17% effective vig due to compounding. The higher payout multiplier comes with a proportionally higher margin cost. Many experienced bettors note this tradeoff — the mathematical efficiency of parlays depends heavily on whether each individual leg represents favorable pricing relative to the true probability.
How does vig compound in a 5-leg parlay?
The vig compounds multiplicatively. At standard -110 on all legs: a single bet has ~4.5% vig, a 2-leg parlay has ~9% effective vig, a 3-leg parlay has ~13%, a 4-leg parlay has ~17%, and a 5-leg parlay has roughly 21% effective vig. At that level, the sportsbook's margin accounts for over one-fifth of the hypothetical fair payout. The compounding table above illustrates the exact progression for any combination of odds.
What is the correlation factor in Same Game Parlays (SGPs)?
Same Game Parlays combine outcomes from a single game (e.g., team to win + player to score 20+ points). Sportsbooks originally priced these as independent events, but outcomes in the same game are often correlated — if a team wins by a large margin, their star player likely performed well. Books now add additional margin to SGPs to account for this correlation, which can result in offered payouts that are significantly lower than what independent-event math would suggest. This calculator helps illustrate that gap by comparing offered payouts to estimated fair payouts.
How many legs can a parlay have?
Most sportsbooks allow 10 to 15 legs, with some permitting up to 25. This calculator supports up to 12 legs. The compounding margin math is worth noting: a 10-leg parlay at standard -110 odds carries roughly 37% effective vig, meaning the sportsbook's margin accounts for more than a third of the hypothetical fair payout. The compounding table above illustrates how this progression works at any leg count.
How is the expected value (EV) of a parlay calculated?
Expected Value (EV) = (Win Probability × Profit) − (Loss Probability × Stake). For a parlay, the win probability is the product of each leg's fair (no-vig) probability. This calculator estimates fair probability for each leg by removing the estimated margin, then computes the parlay EV. A negative EV indicates that the wager's expected return is below breakeven over a large number of repetitions. The "EV Gap" metric illustrates the difference between the offered payout and the estimated fair payout.
Educational use only. ChanceMetrics provides general informational tools and mathematical illustrations. Nothing on this page is betting, investment, legal, or tax advice. Outputs are hypothetical, are not personalized recommendations, and do not suggest that any wager should be placed.
ChanceMetrics provides educational tools and calculators for informational purposes only and does not constitute financial or investment advice. Sports betting involves significant risk of loss. The outputs are mathematical estimates based on hypothetical assumptions and do not guarantee any actual future profit or outcome. Parlay EV estimates use approximate vig removal and may not perfectly reflect actual sportsbook margins.
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