Add up to 12 legs in American odds. We multiply the decimal odds for every leg, apply your stake, and show the true payout, profit, and implied win probability. Last updated: May 2026.
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A parlay is multiplication, not addition. Each leg's American odds are converted to decimal (positive: (odds ÷ 100) + 1; negative: (100 ÷ |odds|) + 1), and then every decimal is multiplied together to produce the combined decimal odds. Your payout = stake × (product of all decimal odds), and profit is that payout minus your stake. Because the prices multiply, payouts balloon quickly — but so does the difficulty of winning, since every single leg must hit.
The calculator also converts the combined decimal back to American odds for readability and computes the parlay's implied win probability as 1 ÷ combined decimal × 100. That implied figure is the mathematical chance all legs land at the prices shown, and it falls fast as you stack legs. Add a leg, and you're multiplying in another number greater than 1.0 to the odds — and another probability less than 100% to your chance of cashing.
The page loads with two default legs, both −110, on a $100 stake. Each −110 converts to (100 ÷ 110) + 1 = 1.909 decimal. Multiply the legs: 1.909 × 1.909 = 3.645 combined decimal odds. Payout = $100 × 3.645 = $364.46, for a profit of $264.46. Converted back, 3.645 decimal is roughly +265 American.
Implied win probability = 1 ÷ 3.645 = 27.43% — already under one-in-three on just two coin-flip legs. Add a third −110 leg and the combined odds become 1.909³ = 6.96 (about +596), with implied probability dropping to 14.4%. A five-leg version at −110 each lands near +2,400 but only about a 3% chance to win. That's the parlay trade-off in numbers: each leg multiplies the payout up and the probability down.
I enjoy a parlay as much as anyone, but the math is honest about what it is: a high-variance, high-hold bet. Treat the big payout as entertainment, stake only what you can afford to lose, and don't mistake a long-shot ticket for an investment.
A parlay combines multiple bets into one wager. The decimal odds of every leg are multiplied together, then multiplied by your stake. Every leg must win or the whole parlay loses.
Convert each leg to decimal odds first. Positive American odds: (odds ÷ 100) + 1. Negative American odds: (100 ÷ |odds|) + 1. Multiply all decimals together to get the parlay's combined decimal odds.
Mathematically, parlays carry a higher hold (built-in house edge) than single bets because the vig compounds with each leg. They can still be +EV if every individual leg is itself +EV, but most casual parlays are -EV.
This calculator supports up to 12 legs. Most sportsbooks cap parlays somewhere between 10 and 25 legs, so 12 covers nearly every real-world bet slip.
Each leg has its own implied probability under 100%. Multiplying probabilities (which is what a parlay is in math terms) compounds them downward fast — a 5-leg parlay with each leg at -110 has only about a 3% true win probability.