Parlay Calculator

A parlay multiplies prices together, and it multiplies the vig along with them. The payout looks generous because the risk compounds faster than the return does.

Add your legs for the combined price and payout. Add a win probability to each one and the calculator also returns the fair price for that ticket, so the gap between fair and offered is visible instead of hidden.

How A Parlay Is Priced

Convert every leg to decimal, multiply them together, and that is the combined price. The payout is the stake times that number.

Worked example. Three legs at -110, -130 and +150. In decimal those are 1.9091, 1.7692 and 2.50.

1.9091 × 1.7692 × 2.50 = 8.4441, which is about +744 in American terms.

A $50 stake returns $422.20, a profit of $372.20. The combined price implies a probability of 1 ÷ 8.4441 = 11.84%.

Now the honest half. If your own probabilities for the three legs are 55%, 60% and 42%, the parlay's true probability is 0.55 × 0.60 × 0.42 = 13.86%, which is worth a fair price of about +621. You are being offered +744 on something you rate at +621 — a positive-expectation ticket, but only because the legs were priced as small edges to begin with. Substitute three coin-flip opinions and the same arithmetic turns sharply negative.

Where The Extra Vig Comes From

Each leg carries the book's margin, and multiplying the prices multiplies the margins too. That is the entire economics of the product.

Two -110 legs pay +264. The fair price on two independent 50% events is +300. The book keeps the difference, and the hold on a two-team parlay works out around 10% — more than double the 4.55% on either leg alone.

By six legs roughly a quarter of the stake is gone before the games start. No handicapping edge available to a retail bettor covers a 24% toll, which is why parlays are a marketing product first and a betting instrument second.

Correlation, And Where The Multiplication Fails

Multiplying probabilities is only valid when the legs are independent. Plenty of popular parlays are not, in both directions.

Positively correlated legs help the bettor: a team's moneyline and the game going over are more likely together than the multiplication implies. Books know this, which is why a genuine same-game parlay is repriced rather than simply multiplied — and the repricing is where the extra margin hides.

Negatively correlated legs hurt: backing a heavy favourite and the under in the same game are pulling against each other, and the true probability is lower than the product of the two.

The practical rule is that if you can explain why two legs are linked, do not price the ticket by multiplying. Use the calculator for independent legs across different games, and read same-game parlays before assuming a correlated ticket is the bargain it appears to be.

When A Parlay Is Defensible

There are two honest cases, and neither is "the payout is bigger".

Genuine independent edges. If you have three separate bets you would place individually, each with real positive expectation, the parlay compounds those edges as well as the vig. Whether the net is positive depends on whether your edge per leg exceeds the extra hold, which is what the expected-value line in the calculator tells you. Small edges do not survive it; large ones sometimes do.

Correlated tickets the book has underpriced. Rare, and mostly a matter of finding a book that multiplies legs it should have repriced.

Everything else is entertainment, and the way to keep it that way is to size it as entertainment. A parlay is a lottery ticket with a house edge of 10–25%; if you enjoy them, put a fraction of a unit on them and book the cost as fun rather than as strategy. The parlays explained guide covers the rest, and expected value is where a single leg should be tested first.

Frequently Asked Questions