Parlay Calculator
Combine 2-10 parlay legs in American, decimal or fractional odds: combined price, payout, profit, and implied probability with and without the bookmaker's margin.
Parlay Calculator: with the default inputs, total payout is $2,733.47.
What you are risking on the whole parlay.
All legs are read in this notation.
Legs past the number you set below are ignored.
Stake returned plus winnings, if every leg wins.
- Profit
- $2,633.47
- Combined decimal odds
- 27.3347
- Combined American odds
- +2,633
- Combined fractional odds
- 2633/100
- Implied probability
- 3.66%The break-even chance built into the price you were quoted.
- Probability with the margin removed
- 3.04%
- Bookmaker's margin on the parlay
- 16.97%Share of the stake the priced-in margin keeps, on average, over many identical bets.
- Expected return on the stake
- $83.03Stake minus the margin above. Negative by construction whenever the margin is above zero.
- Legs combined
- 4
Assumptions
- Legs are treated as independent, which correlated and same-game parlays are not.
- The parlay price is the exact product of the legs; sportsbooks may post a different number.
- The margin is assumed identical on every leg and split evenly across both sides of each market (proportional de-vigging).
- This is arithmetic on odds already offered. It is not betting advice and it does not identify a profitable bet.
| As entered | Decimal | Implied % | Margin removed % | Payout after this leg | |
|---|---|---|---|---|---|
| Leg 1 | -110 | 1.9091 | 52.38% | 50% | $190.91 |
| Leg 2 | -110 | 1.9091 | 52.38% | 50% | $364.46 |
| Leg 3 | +150 | 2.5 | 40% | 38.18% | $911.16 |
| Leg 4 | +200 | 3 | 33.33% | 31.82% | $2,733.47 |
The margin-removed column divides each leg's implied probability by the market's overround. It is an estimate built from the margin you entered, not a quoted price.
How this is worked out
The formula
decimal odds: American +X → 1 + X/100; American −X → 1 + 100/X; fractional a/b → 1 + a/b combined odds = decimal₁ × decimal₂ × … × decimalₙ payout = stake × combined odds profit = payout − stake implied probability = 1 ÷ combined odds margin removed: fair probability = implied probability ÷ (1 + margin)ⁿ margin kept on the parlay = 1 − (1 + margin)⁻ⁿ
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Stake
- What you are risking on the whole parlay.in dollars · 0 or more · defaults to 100
- Number of legs
- A number.from 2 to 10 · whole numbers only · defaults to 4
- Odds format
- All legs are read in this notation.American (-110, +150) · Decimal (1.91, 2.50) · Fractional (10/11, 5/2)
- Leg 1
- Legs past the number you set below are ignored.up to 12 characters · defaults to "-110"
- Leg 2
- Free text.up to 12 characters · defaults to "-110"
- Leg 3
- Free text.up to 12 characters · defaults to "+150"
- Leg 4
- Free text.up to 12 characters · defaults to "+200"
- Leg 5
- Free text.up to 12 characters · defaults to "-125"
- Leg 6
- Free text.up to 12 characters · defaults to "+120"
- Leg 7
- Free text.up to 12 characters · defaults to "-110"
- Leg 8
- Free text.up to 12 characters · defaults to "+180"
- Leg 9
- Free text.up to 12 characters · defaults to "-150"
- Leg 10
- Free text.up to 12 characters · defaults to "+250"
- Bookmaker margin per leg(under More options)
- The overround on the market each leg came from. A two-way market priced -110 / -110 is 4.76%.a percentage · from 0 to 50 · defaults to 4.76
What you get back
- Total payoutmain answer
- Stake returned plus winnings, if every leg wins.
- Profit
- Combined decimal odds
- Combined American odds
- Combined fractional odds
- Implied probability
- The break-even chance built into the price you were quoted.
- Probability with the margin removed
- Bookmaker's margin on the parlay
- Share of the stake the priced-in margin keeps, on average, over many identical bets.
- Expected return on the stake
- Stake minus the margin above. Negative by construction whenever the margin is above zero.
- Legs combined
What this assumes
- Legs are treated as independent, which correlated and same-game parlays are not.
- The parlay price is the exact product of the legs; sportsbooks may post a different number.
- The margin is assumed identical on every leg and split evenly across both sides of each market (proportional de-vigging).
- This is arithmetic on odds already offered. It is not betting advice and it does not identify a profitable bet.
About this calculator
A parlay (an accumulator, a multi) is a single bet that needs every leg to win. The arithmetic is short: convert each leg to decimal odds, multiply them, and multiply by the stake. This calculator does that for two to ten legs in American, decimal or fractional notation, and then shows the part most payout calculators leave out — how much of the price is the bookmaker's margin.
How the conversion works
Decimal odds are the only form that multiplies, so everything is converted to them first. American +150 means $150 profit on $100, so it is 2.50 decimal. American −110 means $110 risked to win $100, so it is 1 + 100/110 = 1.9091. Fractional 5/2 is 1 + 5/2 = 3.50. Decimal odds already include your stake, which is why evens is 2.00 rather than 1.00.
Implied probability, and the margin
One divided by the combined decimal odds is the implied probability: the chance at which this bet would break even at the price you were offered. Two legs at −110 combine to 3.6446, so the break-even chance is 27.44%.
That number is not the bookmaker's estimate of the real chance, because the posted price includes a margin. A two-way market priced −110 / −110 sums to 104.76% rather than 100%; the extra 4.76% is the overround. Dividing each leg's implied probability by that overround gives a margin-removed estimate — 50% per leg here, so 25% for the pair.
The gap between those two numbers is the point of this page. A 4.76% margin per leg becomes 8.9% over two legs, 17.0% over four and 31.1% over eight, because the margin compounds exactly as the odds do. That is the single reason a parlay's expected return falls as legs are added while the advertised payout rises.
What this does and does not tell you
This is arithmetic on a price you were already quoted. It cannot tell you whether a leg will win, and nothing in it constitutes a recommendation to place a bet. The margin-removed probability is an estimate that assumes each market's overround matches the figure you entered and is split evenly across both sides — a reasonable approximation for a balanced two-way market and a rough one for long shots, where books typically charge more.
Sportsbooks are also free to price parlays at their own posted odds rather than the true product of the legs, and often do on correlated markets, same-game parlays and "boosted" specials. If the number here does not match the slip, the slip is what you will be paid.
Frequently asked questions
▸How is a parlay payout calculated?
Convert every leg to decimal odds, multiply them together, then multiply by your stake. That product is the total returned; subtract the stake for profit.
▸Why does a 4-leg parlay pay less than the odds suggest it should?
Each leg's price already contains the bookmaker's margin, and multiplying the legs multiplies the margins too. At 4.76% per leg the margin on the parlay is 17.0%, against 4.76% on a single bet.
▸What is implied probability?
One divided by the decimal odds — the break-even chance at that price. It is higher than the bookmaker's own estimate of the chance, by roughly the market's overround.
▸Does adding a leg improve a parlay?
It raises the advertised payout and lowers the chance of winning, and it adds the new leg's margin on top of the existing ones. The arithmetic is on this page; the decision is not.
▸Why does my sportsbook quote different odds than this?
Books are free to post their own parlay price rather than the exact product of the legs, and same-game and correlated parlays are usually priced separately. The slip is what pays.
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