This calculator gives the total odds, the potential return, and above all the margin the bookmaker stacks up with each added leg.
Margins multiply too
What the calculation hides: the margin multiplies as well. At 5% margin per leg, a four-leg parlay stacks about 21%. An eight-leg parlay exceeds 45%.
| Legs | Stacked margin (5% per leg) | Effective payout rate |
|---|---|---|
| 1 | 5,0 % | 95,2 % |
| 2 | 10,3 % | 90,7 % |
| 4 | 21,6 % | 82,3 % |
| 6 | 34,0 % | 74,6 % |
| 10 | 62,9 % | 61,4 % |
That is why French bookmakers push parlays and their associated “boosts”: it is where their margin is most comfortable, while staying under the annual payout cap.
Is a parlay ever worth it?
Mathematically, a parlay only has positive expectation if every leg has one. Multiplying negative-expectation bets only deepens the expected loss.
Two cases where a parlay can still be defended:
- Odds boosts. When an operator artificially raises the odds of a pre-built parlay, it can create genuine value. Check it with the EV calculator.
- Correlated events poorly accounted for by the bookmaker — a “win + over 2.5 goals” parlay on a team that rarely wins 1-0, for instance. Many operators now block these combinations.
Frequently asked questions
Are parlays or singles the better play?
Singles, as soon as they have positive expectation: at equal expectation, a parlay adds variance and stacks margins. Stats&Bet sends value singles detected one by one on French bookmakers.
Why do my parlays always lose?
Because probability multiplies too: four legs at 60% each give only a 13% chance of all landing. Add the bookmaker's stacked margin, and the parlay becomes the worst product in the catalogue.
Can a parlay be profitable with value betting?
Only if each leg is individually positive-expectation, and provided the legs are independent. In practice it is better to play the bets separately: same expectation, far lower variance.
Are odds boosts worth taking?
Sometimes. A boost taking a parlay from 8.00 to 10.00 adds 25% to the price, which can be enough to offset the stacked margin. Always compute the fair odds of the legs before accepting, rather than trusting the advertised percentage.