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Add legs to build your parlay
Add at least 2 legs using the builder, then click Calculate Parlay to see the full analysis.
Add up to 12 legs. Instantly see combined odds, true win probability, total payout, and real expected value — before you place the bet.
Add at least 2 legs using the builder, then click Calculate Parlay to see the full analysis.
Learn exactly when parlays make mathematical sense: correlated legs, boosted odds, and same-game parlay angles for US, UK & Canada bettors.
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Each leg multiplies the combined odds in decimal form. Our tool shows exactly how win probability compounds down as you add more legs — the math most bettors never see.
See whether your parlay has positive or negative expected value based on the true probability of all legs winning. Standard vigged parlays are almost always -EV — our tool proves it.
The vig compounds with every leg you add. This tool shows exactly how much of the bookmaker's edge you're absorbing with each additional leg.
Parlays are the most popular bet type at US sportsbooks — and also the most profitable product for the house. Understanding the math tells you exactly when a parlay makes sense and when you're simply donating money to the bookmaker.
A parlay combines multiple bets. All legs must win. The odds multiply in decimal form: a 3-team parlay with three -110 lines gives you 2.37 × 2.37 × 2.37 ≈ 13.3x your stake. That sounds attractive — until you realize the true probability of winning all three legs is approximately 12.5%, while the parlay pays as if it's only 7.5% probable (1/13.3). The gap between 12.5% and 7.5% is the compounded vig you're paying the bookmaker.
At standard -110 lines, the book holds about 4.55% per leg. With two legs that's 9.1% total margin. With four legs it approaches 18%. This compounds aggressively — which is why books heavily market parlays and teasers.
Three specific scenarios can make parlays +EV. First: if each individual leg is genuinely +EV (you've found a mispriced line), a parlay of +EV legs is mathematically positive. Second: correlated parlays, where two outcomes are positively correlated (e.g., a high-scoring team covering AND the game going over). When legs are correlated, the true combined probability is higher than the book's independent-probability model assumes. Third: promotional pricing — boosted odds that flip the EV in your favor.
Same-game parlays are extremely popular on FanDuel and DraftKings. They're also among the worst-value bets available. Books heavily adjust SGP prices to account for correlations, then add their standard margin on top. In many cases, the true EV of an SGP is -20% to -40%, meaning you lose 20-40 cents of every dollar wagered in expectation. Our parlay calculator can analyze any SGP — just enter each leg's American odds and see the real numbers.
The one scenario where a two-leg parlay can make strategic sense: when both legs are independently +EV and you want to reduce the correlation of your daily results. Betting both legs separately exposes you to two independent outcomes; parlaying them converts two moderate gains into one large win or a complete loss. This is neither better nor worse from an EV perspective (assuming no extra vig), but changes your variance profile significantly.