To calculate parlay odds, convert every leg to decimal odds, multiply the decimal values together, and multiply the result by your stake to find the total payout. Subtract the original stake from the payout to find profit. Because every leg must win, the parlay's probability declines as more selections are added.
Run the numbers on your own ticket with the free parlay calculator, or compare every leg count at once in the parlay odds chart.
Parlay odds formula
Combined decimal odds = leg 1 decimal odds × leg 2 decimal odds × … × leg n decimal odds
Total payout = stake × combined decimal odds
Profit = total payout − stake
For example, three legs priced at 1.91 decimal produce combined odds of:
1.91 × 1.91 × 1.91 = 6.9679
A $20 stake would return $139.36 in total, including $119.36 of profit.
Two-leg parlay example using American odds
Suppose both legs are priced at −110.
- Convert −110 to decimal odds:
1 + (100 / 110) = 1.9091. - Multiply the two legs:
1.9091 × 1.9091 = 3.6446. - Multiply by the stake. A $25 stake returns $91.12.
- Subtract the $25 stake. The profit is $66.12.
The combined American price is approximately +264.
Three-leg parlay example with mixed odds
| Leg | American odds | Decimal odds |
|---|---|---|
| Team A | −120 | 1.8333 |
| Team B | +135 | 2.3500 |
| Team C | −105 | 1.9524 |
Combined decimal odds:
1.8333 × 2.3500 × 1.9524 ≈ 8.412
A $10 stake returns approximately $84.12, including $74.12 in profit.
How to convert American odds before multiplying
For positive American odds:
decimal odds = 1 + (American odds / 100)
Example: +150 becomes 1 + 1.50 = 2.50.
For negative American odds:
decimal odds = 1 + (100 / absolute American odds)
Example: −200 becomes 1 + 0.50 = 1.50.
Use the odds converter when the legs use different formats.
How parlay win probability is calculated
When the outcomes are independent, multiply the probability of every leg.
Three true 50% outcomes have a combined probability of:
0.50 × 0.50 × 0.50 = 0.125, or 12.5%.
That means the parlay would win once in 8 attempts on average if each leg were truly independent and exactly 50% likely. Sportsbook odds include margin, so the implied probability derived from posted prices should not automatically be treated as the true probability.
Why the sportsbook margin compounds
A parlay does not remove the vig attached to each selection. It combines the priced legs, which means small margins can compound across the ticket. Adding more legs increases the headline payout, but it also increases the chance that at least one leg loses.
Correlation matters too. Two legs from the same game may not be independent. Sportsbooks account for this in same-game parlay pricing rather than simply multiplying the displayed odds.
Parlay payout versus profit
These terms are different:
- Payout is the total amount returned, including the original stake.
- Profit is the payout minus the original stake.
A $20 bet returning $100 has a $100 payout and an $80 profit.
A note on rounding
Decimal odds are shown here rounded for display, while the payouts are calculated from the unrounded values and then rounded to the cent. Multiplying a rounded decimal by your stake can therefore differ from the figures above by a few cents. A sportsbook applies its own rounding rules, which is one of several reasons its slip may not match a hand calculation exactly.
Next steps
Frequently asked questions
Do you add or multiply parlay odds?
Multiply decimal odds. Do not add American odds together.
How do you calculate a parlay with different odds formats?
Convert every leg to decimal odds first, then multiply the decimal values.
Why does my sportsbook show a different payout?
Possible reasons include rounding, boosted odds, correlated selections, alternate lines, rules for voided legs, or a sportsbook-specific same-game parlay model.
What happens if one leg pushes?
Rules vary by market and sportsbook. In many standard parlays, a pushed leg is removed and the ticket is recalculated with the remaining legs. Always confirm the book's house rules.
What does a 3-leg parlay at −110 return?
Combined decimal odds of 6.96, or about +596 in American terms — $69.58 back on a $10 stake, before sportsbook-specific rounding. The parlay odds chart lists every leg count from 2 to 12.
Related: parlay calculator · parlay odds chart · odds converter · EV and Kelly calculator · betting glossary
This guide explains how a betting market works and how the arithmetic is done. It is information, not betting advice: Nebula Insights publishes no picks, no selections and no recommended wagers. Sportsbook rules vary by book and jurisdiction — always confirm the house rules that apply to your account. 18+ only.