Parlay Calculator

What this parlay calculator does

Add up to 12 legs to a parlay. Each leg has American odds, an optional win percentage, and a push toggle. A push leg is removed from the parlay, so a 4-leg parlay with one push pays like a 3-leg parlay.

The calculator shows the combined decimal and American odds, the payout and profit for your stake, and the implied probability. When every live leg has a win percentage, it also shows the true parlay probability, the fair American odds, and the expected value per bet.

How the math works

The combined decimal odds are the product of each leg's decimal odds. A 2-leg parlay at 2.0 and 1.5 has combined decimal odds of 3.0. The payout is the stake times the combined decimal. The profit is the payout minus the stake.

The implied probability is 1 divided by the combined decimal. The true parlay probability is the product of each leg's win percentage as a decimal. The fair American odds come from the true probability, and the EV is the stake times (true probability times combined decimal minus 1).

Worked example

Two legs at -110 each (decimal 1.909). The combined decimal is 3.645, the combined American is +264, and a $100 stake pays $364.50 total ($264.50 profit). The implied probability is 27.44 percent.

If you set each leg's win percentage to 55 percent, the true parlay probability is 30.25 percent, the fair American odds are +231, and the EV per $100 is $10.25. That means the parlay is worth more than it pays, which is rare.

Common mistakes

The most common mistake is treating a push as a loss. A push removes the leg from the parlay, so the payout drops to the product of the remaining legs. The calculator handles that with the push toggle.

Another mistake is using the bookmaker's implied probability as the true chance. Implied probability includes the vig. Enter your own win percentage for each leg to get the true parlay probability and EV.

Frequently asked questions