How to Calculate Parlay Payouts

A parlay combines several bets into one. The payout is larger because the probability of hitting all of them is smaller, and the two scale together — right up until the sportsbook's margin is taken into account, at which point they stop scaling together quite so neatly.

The calculation

Three steps.

1. Convert each leg to decimal odds. Positive American prices: (odds ÷ 100) + 1. Negative: (100 ÷ |odds|) + 1.
2. Multiply the decimal odds together. This gives the combined decimal price.
3. Multiply by your stake. The result is your total return, stake included. Subtract the stake for profit.

A two-leg example

Two legs at -110 and +160, with a $50 stake.

Combined: 1.909 × 2.600 = 4.964

Total return: 50 × 4.964 = $248.18

Profit: $198.18

In American odds, 4.964 is +396.

A four-leg example

Four legs at -110, -120, +105 and -140, staking $25.

Combined: 1.909 × 1.833 × 2.050 × 1.714 = 12.296

Total return: 25 × 12.296 = $307.40

Profit: $282.40

Why the payout is smaller than it should be

Here is the part that is rarely spelled out on a bet slip.

Each -110 leg implies a 52.38% probability. But the sportsbook has two sides at 52.38%, totalling 104.76%, so the true probability of a typical spread leg is closer to 50%.

Work out the fair payout for three coin flips: the chance of hitting all three is 0.5 × 0.5 × 0.5 = 12.5%, which is a fair decimal price of 8.00, or +700.

The actual payout for three -110 legs is 1.909³ = 6.96, or +596.

That is the honest case against long parlays. It is not that they lose more often — of course they do, that is the trade. It is that they return proportionally less than the extra risk justifies, and the gap grows with every leg added.

Pushes and voided legs

If a leg lands exactly on the number — a team favoured by 7 winning by exactly 7 — that leg pushes. Almost every sportsbook then removes the leg and recalculates the parlay at the remaining legs' combined odds. A four-leg parlay with one push pays as a three-leg parlay.

This is worth knowing because it changes your realistic payout, and because buying a half-point to avoid a push is sometimes cheaper than the push risk you are removing.

Correlated legs and same-game parlays

Standard parlay pricing assumes the legs are independent — that one outcome tells you nothing about another. Within a single game, that assumption usually fails. If a quarterback throws for 350 yards, his team scoring over the total becomes more likely, not less.

Sportsbooks know this, which is why same-game parlays are priced through a correlation model rather than by multiplying the legs. The published price will be lower than the multiplication suggests, and the difference is the sportsbook's correction — plus, typically, a larger margin than a straight parlay carries.

The practical implication: do not calculate a same-game parlay by multiplying the individual leg prices, because the sportsbook will not pay that. Use the price shown on the slip.

Do parlays have a place?

Two defensible uses.

Entertainment with a known cost. A small stake on a long parlay bought as entertainment, with the 20%+ house edge understood and accepted, is a reasonable purchase. Many things cost more per hour.

Genuinely mispriced legs. If every individual leg is one you believe is priced wrong in your favour, the edges multiply too. This is rare, demanding, and not the reason most parlays are placed.

What does not work is the common framing — that parlays are a way to turn a small stake into a large one. They are, occasionally. The price of that occasional outcome is a significantly worse long-run return than betting the same legs separately.

Related reading

• How to use a parlay calculator — reading the output, and the three mistakes people make entering legs.
• American odds vs decimal odds — the conversions this article depends on.
• How to remove the vig from betting odds — finding the sportsbook's actual probability estimate underneath the margin.