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Parlay odds calculator: payout, implied probability and fair odds
Enter each leg's American odds. Add the other side of the market (the under, if you took the over) to see the no-vig fair odds and how much margin the book is holding on your parlay.
Odds are examples to start you off; replace them with your own. Treats legs as independent (different games). Not a prediction of any result.
Have a screenshot instead? The bet slip checker reads it, fills in today's FanDuel and BetMGM prices and flags anything that changed.
How the parlay calculator works
- Convert each price to decimal. Positive odds:
1 + odds / 100. Negative odds:1 + 100 / |odds|. So −110 is 1.909 and +120 is 2.20. - Multiply the decimals. That is the parlay's decimal odds. Payout is
stake × decimal, stake included. - Implied probability is
1 / decimal: the chance the payout is priced around, with the book's margin still in it. - No-vig chance per leg is
p(your side) / (p(your side) + p(other side)). Multiply those for the parlay's fair chance. - Book margin on the parlay is
1 − fair chance × decimal odds: the share of each dollar the price keeps on average if the fair chances are right.
Parlay odds at −110 per leg
The most common prop price is −110 on both sides. Here's what stacking those legs does. The "fair" column assumes every leg is a true 50/50.
| Legs | Parlay odds | Implied chance | Fair chance | Average return per $100* |
|---|---|---|---|---|
| 1 | −110 | 52.4% | 50.0% | $95.45 |
| 2 | +264 | 27.4% | 25.0% | $91.12 |
| 3 | +596 | 14.4% | 12.5% | $86.97 |
| 4 | +1228 | 7.5% | 6.3% | $83.02 |
| 5 | +2436 | 3.9% | 3.1% | $79.25 |
| 6 | +4741 | 2.1% | 1.6% | $75.64 |
*Over many bets, if each leg is truly 50/50. Each added −110 leg keeps another ~4.5% of the stake on average. That's why a leg only belongs in a parlay if you'd bet it on its own.
Same game parlays are different
This calculator multiplies legs as if they were independent, which is right for legs from different games. Legs from the same game move together (a quarterback's passing yards and his top receiver's yards, say), so FanDuel and BetMGM price a Same Game Parlay with their own correlation models. Their number can be well below the multiplied one. More in same game parlay correlation, explained.
Frequently asked questions
How do you calculate parlay odds?
Convert each leg's American odds to decimal (positive odds: 1 + odds/100; negative odds: 1 + 100/|odds|), multiply the decimals together, then convert back. Three legs at −110 are 1.909 × 1.909 × 1.909 = 6.96, which is about +596.
How do you calculate parlay payout?
Payout = stake × combined decimal odds, and that includes your stake. A $10 bet at a combined 6.96 returns about $69.58 if every leg lands.
What is the implied probability of a parlay?
It is 1 divided by the combined decimal odds. At +596 (6.96 decimal) the slip implies about 14.4%, roughly 1 in 7. That's the break-even rate the payout is built around, not a prediction.
What are no-vig fair odds?
Each two-sided market (over/under) carries a margin, so both sides add up to more than 100%. Enter the other side's price for each leg and the calculator scales the pair back to 100% to estimate the fair chance, then multiplies them for the parlay.
Why does my sportsbook pay less than this calculator?
Usually because some legs are from the same game. Books price same game parlays with their own correlation models, so the payout differs from straight multiplication. Rounding and odds boosts also change it.
Does this work for same game parlays?
It gives the payout for independent legs. For a same game parlay the book's own price is what counts; compare it to this number to see how much the book adjusted it. See same game parlay correlation.
Related guides
Model picks, not locks. No checker can tell you a slip will win; it can only show you the price, the math and what changed. 21+ only. If betting stops being fun, call 1-800-GAMBLER or read our responsible gaming page.