Parlay Betting Explained
Everything about parlays: how they work, the math behind them, same-game parlays, correlated parlays, and strategies to improve your success rate.
Parlays are the most exciting — and most misunderstood — bet type in sports betting. By combining multiple wagers into a single bet, parlays offer massive potential payouts that make them irresistible to bettors. But that excitement comes with significant mathematical headwinds. Understanding parlay math, optimal leg counts, and correlation strategies separates profitable parlay bettors from those who are simply buying lottery tickets. This guide covers everything you need to know about parlays, from basic mechanics to advanced strategies.
What Is a Parlay Bet?
A parlay is a single bet that combines two or more individual selections (called 'legs') into one wager. All legs must win for the parlay to pay out — if any single leg loses, the entire bet is graded as a loss. In exchange for this increased risk, parlays offer significantly higher payouts than individual bets. Parlays are available across all sports and can combine different bet types — you might parlay an NFL spread with an NBA moneyline and an NHL total. Most sportsbooks allow parlays of up to 12-15 legs, though some permit even more. Some sportsbooks automatically void a leg (rather than losing the parlay) if a game is canceled or postponed, adjusting the payout accordingly.
Example
A 3-leg parlay combining Chiefs -3 (-110), Lakers ML (-150), and Oilers/Flames Over 6.5 (-110) pays approximately 5.9:1. A $50 bet returns about $345 total ($295 profit) if all three legs win.
The Math Behind Parlays
Parlay payouts are calculated by multiplying the decimal odds of each leg together. For two -110 legs: 1.909 × 1.909 = 3.645, meaning a $100 bet returns $364.50. The true odds of hitting a 2-leg parlay of coin-flip propositions is 25% (1 in 4), but the parlay pays 2.64:1 instead of the true 3:1. This gap is the sportsbook's built-in edge, and it compounds with each additional leg. For a 3-leg parlay at -110 each, the true odds are 12.5% (1 in 8), but the payout is about 6:1 instead of 7:1. By the time you reach a 10-leg parlay, the sportsbook's edge has compounded to a massive 15-20%. This compounding edge is why sportsbooks love parlays — they're among the most profitable bet types for the house.
Warning
The sportsbook's edge compounds with each leg. A 2-leg parlay has roughly a 3% edge against you, but a 10-leg parlay can have a 15-20% edge. Keep parlays short to minimize the house advantage.
Optimal Parlay Size
From a pure mathematical standpoint, the optimal parlay size is 2-3 legs. At this size, the compounding house edge is manageable, the hit rate is sustainable, and the payouts are still significantly better than straight bets. Professional bettors who use parlays almost exclusively stick to 2-leg parlays because the math is most favorable. For recreational bettors, 3-4 legs offer a good balance of excitement and realistic hit probability. Five-leg parlays hit roughly 3% of the time, which means you need substantial payouts to overcome the long losing streaks. Beyond 5 legs, parlays become extremely difficult to sustain profitably unless you have a significant edge on every individual leg.
Pro Tip
If you must bet large parlays, allocate only a small percentage of your bankroll (0.5-1%) per bet. Parlays are high-variance by nature and require strict bankroll discipline.
Same-Game Parlays (SGPs)
Same-game parlays let you combine multiple bets from a single game — for example, combining a team's spread with a player prop and the game total. SGPs have become hugely popular since DraftKings and FanDuel introduced user-friendly builders. However, SGPs carry a higher house edge than traditional parlays because the outcomes are correlated. When you parlay a team's spread with a player prop from the same game, those outcomes aren't independent — if the team is winning big, certain player props are more likely to hit. Sportsbooks account for this correlation in their SGP pricing, often offering lower payouts than a traditional parlay of the same selections would yield. Despite the higher edge, SGPs can be profitable if you specialize in identifying correlations the sportsbook's algorithm doesn't fully capture.
Correlated Parlays
Correlated parlays exploit logical connections between outcomes to improve your probability of winning. The concept is simple: some outcomes are more likely to happen together than independently. For example, a game where both teams are expected to score a lot (over on the total) is more likely to produce a high-scoring first half (first-half over) — these events are positively correlated. Parlaying an underdog moneyline with the under is another positive correlation, because underdogs often win low-scoring, close games. Traditional sportsbooks have gotten better at detecting and restricting correlated parlays, but SGP builders sometimes allow correlations that traditional markets wouldn't. Identifying positive correlations is one of the few ways to gain a mathematical edge on parlays.
Example
Parlaying Bills ML (underdog) + Under 45.5: If the Bills win as an underdog, it's more likely to be a close, lower-scoring game. These outcomes are positively correlated, meaning the parlay has a higher true probability of winning than the individual probabilities would suggest.
Parlay Hedging and Cash-Out Strategies
When a parlay has only one leg remaining, you have the option to hedge by placing a separate bet on the opposite side of your remaining leg. This guarantees a profit regardless of the outcome, though it reduces your maximum win. The decision to hedge depends on several factors: the size of the potential payout, your bankroll, and your risk tolerance. As a general rule, consider hedging when the remaining payout exceeds 10× your original bet. Most sportsbooks also offer 'cash out' on parlays, letting you settle for a guaranteed amount before all legs are decided. Cash-out pricing typically includes a 5-10% margin that favors the sportsbook, so manual hedging often yields a better return — but cash out is more convenient and available on more platforms.
📝 Key Takeaways
- All legs must win for a parlay to pay out
- The house edge compounds with each additional leg — keep parlays to 2-4 legs
- Same-game parlays carry higher margins due to correlated outcomes
- Correlated parlays can provide an edge when you identify connections the book misses
- Consider hedging large parlays when only one leg remains
- Allocate a small bankroll percentage (0.5-2%) to each parlay bet