How are parlay odds calculated?

Each leg is converted to decimal odds and all of them are multiplied together. Three legs at 1.9091, 2.50 and 1.8333 multiply to 8.75, which is +775 in American odds.

Why do the odds get so long?

Every leg must win, so the probabilities multiply and the combined chance drops quickly. Three roughly even-money legs already imply only about an 11% chance, which is why the payout is large.

Are parlays a good bet?

Each leg carries the book's margin, and those margins compound across the parlay, so the total margin is higher than on a single bet. The payout is bigger, but so is the edge the book holds. This tool only does the math.

Can legs in the same game be combined here?

This calculator multiplies the odds as if the legs are independent. Legs from the same game are often correlated, and books price those as same-game parlays with different odds, which this tool does not model.

Free calculator

Parlay calculator

Combine 2 to 8 legs into one parlay. Enter each leg's American odds and your stake to see the combined odds, the implied probability, and what the parlay pays.

Leg 1

Leg 2

Leg 3

3 of 8 legs

Stake

Decimal odds

8.75

American odds

+775

Implied probability

11.43%

Payout

$875.00

Profit

$775.00

For information only. Not betting advice.

How it works

A parlay, or accumulator, combines several bets into one. Every leg must win for the parlay to pay, and the odds multiply. Convert each leg to decimal odds, multiply them all together, and that product is the parlay's decimal odds.

The payout is your stake times the combined decimal odds, and the profit is the payout minus the stake. The implied probability is 1 divided by the combined decimal odds, which falls fast as you add legs.

Because each leg carries its own margin, those margins compound across a parlay. The more legs, the larger the total margin working against the bettor, even though the payout looks big.

Worked example

Three legs at -110, +150 and -120 convert to decimal 1.9091, 2.50 and 1.8333. Multiplied, that is a combined 8.75 in decimal odds, or +775 in American. The implied probability is 1 / 8.75 = 11.43%. A $100 stake pays $875.00, a profit of $775.00.

Questions

How are parlay odds calculated?: Each leg is converted to decimal odds and all of them are multiplied together. Three legs at 1.9091, 2.50 and 1.8333 multiply to 8.75, which is +775 in American odds.
Why do the odds get so long?: Every leg must win, so the probabilities multiply and the combined chance drops quickly. Three roughly even-money legs already imply only about an 11% chance, which is why the payout is large.
Are parlays a good bet?: Each leg carries the book's margin, and those margins compound across the parlay, so the total margin is higher than on a single bet. The payout is bigger, but so is the edge the book holds. This tool only does the math.
Can legs in the same game be combined here?: This calculator multiplies the odds as if the legs are independent. Legs from the same game are often correlated, and books price those as same-game parlays with different odds, which this tool does not model.

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