A parlay combines two or more picks into one. Every pick, called a leg, has to win for the parlay to win. In return, the payout is much bigger than any single pick. That big number is exactly what makes parlays so tempting, and so hard to win.
How a parlay works
You choose several outcomes, for example:
- Team A to win (moneyline)
- Team B -3.5 (spread)
- Game C over 45.5 (total)
If all three hit, you win the combined payout. If even one misses, the whole parlay loses. Some platforms treat a push on one leg by removing it and recalculating the payout with the remaining legs.
Calculating parlay odds
The easiest way is with decimal odds. Multiply the decimal odds of each leg.
Worked example with three legs at -110 (decimal 1.91):
- 1.91 × 1.91 × 1.91 = 6.96
A stake of 10 returns 69.60, for 59.60 profit. In American odds, that is about +596.
Now add more legs at 1.91:
| Legs | Decimal | Approx. American | |---|---|---| | 2 | 3.64 | +264 | | 3 | 6.96 | +596 | | 4 | 13.30 | +1230 | | 5 | 25.40 | +2440 | | 6 | 48.50 | +4750 |
The payouts grow fast, which feels exciting.
Why parlays are hard to win
Now look at the probabilities. If each leg is a true 50/50, the chance of all legs winning is 0.5 multiplied by itself.
| Legs | Chance all win | |---|---| | 2 | 25.0% | | 3 | 12.5% | | 4 | 6.25% | | 5 | 3.1% | | 6 | 1.6% |
A 5-leg parlay at 50/50 legs hits about once in 32 tries. Most of the time you lose.
The margin compounds
Here is the hidden problem. Every leg carries a house margin. When you multiply legs together, the margins multiply too.
At -110, each leg implies 52.4% instead of 50%. For a fair coin flip, the true fair payout for 3 legs would be 8.00 (a 1 in 8 chance). The parlay pays 6.96. That gap means the house edge on a 3-leg parlay is about 13%, compared with about 4.5% on a single -110 pick.
The more legs, the bigger the edge against you. That is why parlays are among the most profitable products for sportsbooks. See why sportsbooks win in the long run.
Worked example: "safe" favorites
Many people build parlays out of heavy favorites because each one "can't lose."
Three legs at -250 (decimal 1.40):
- Combined odds: 1.40 × 1.40 × 1.40 = 2.74 (about +174)
- Implied chance of each: 71.4%
- Implied chance all three win: 0.714 × 0.714 × 0.714 = 36.4%
So your "safe" parlay loses almost two times in three. Favorites lose regularly, and stacking them multiplies the risk.
Correlated legs
Sometimes legs are linked. If you pick a team to win by a lot and the game to go over, those outcomes can move together. Platforms usually limit or adjust these combinations, sometimes called same-game parlays, and price them accordingly. The pricing on same-game parlays typically includes a larger margin, not a smaller one.
Are parlays ever a good idea?
Parlays are fine as entertainment, as long as you understand the math:
- Treat them as small, fun picks, not a strategy.
- Keep the number of legs low.
- Never increase your stake to "make up" for a parlay that just missed by one leg.
If each of your legs genuinely has an edge, a parlay can amplify it. But most people do not have an edge on every leg, and a parlay amplifies the house's edge instead.
The "one leg away" feeling
Parlays create lots of near-misses. Losing a 5-leg parlay on the last leg feels like you almost won. In reality, you were always much more likely to lose. That feeling can encourage chasing. Our guide on the gambler's fallacy covers this and other traps.
Try parlays with play money
The best way to understand parlays is to see the results over time. On MockSport you can build free play-money parlays with virtual tokens and compare your hit rate to your single picks. Most people quickly see how rarely big parlays land. There are no deposits and no prizes, so it is a safe way to learn the lesson. Check today's odds to start.
FAQ
What happens if one leg of a parlay pushes?
On many platforms, the pushed leg is removed and the parlay is paid on the remaining legs at reduced odds. Rules vary, so check them.
Why are parlay payouts so big?
Because the chance of every leg winning is small. The payout multiplies with each leg, but so does the probability of losing.
How many legs should a parlay have?
Fewer is better from a math standpoint. Each extra leg increases the house edge and lowers your chance of winning.