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A parlay's house edge is not fixed — it grows with every leg you add, because the sportsbook's built-in margin (the vig, or juice) compounds across each selection. A two-leg parlay where both sides are priced at −110 carries roughly a 5% house edge; stack five of those same legs together and the edge can exceed 25%, according to payout analysis from multiple parlay calculators.
What Is the Vig, and Why Does It Compound?
Every −110 line implies a 52.38% win probability when it should imply 50%. That extra 2.38% is the sportsbook's margin. On a single straight bet it costs you a small, predictable amount. On a parlay, however, each leg's vig multiplies against the others. You are not adding margins — you are multiplying them. The deeper the ticket, the further actual payouts fall behind mathematically correct ones.
To see this concretely, check the full parlay payout table showing what each leg count pays at −110. A five-leg ticket should return 31:1 at true probability but typically pays only around 24:1 at licensed US sportsbooks. That gap is the compounded vig made visible.
How Does the Parlay House Edge Compare Leg by Leg?
| Legs (all at −110) | Correct odds (true probability) | Typical sportsbook payout | Approx. house edge |
|---|---|---|---|
| 2 | 3:1 | ~2.6:1 | ~5% |
| 3 | 7:1 | ~6:1 | ~10–12% |
| 4 | 15:1 | ~12:1 | ~15–18% |
| 5 | 31:1 | ~24:1 | 25%+ |
How Does This Affect Real Dollar Returns?
A $100 two-leg parlay with both legs at −110 pays roughly $264 profit on a win. Mathematically correct odds would pay $300. That $36 shortfall is the compounded vig at work. Scale to a five-leg $100 ticket and the sportsbook payout is approximately $2,435, while the true-odds payout would be $3,100. You are giving up hundreds of dollars on a single ticket simply because margins multiply.
For a step-by-step look at the decimal multiplication behind these numbers, see the guide to how parlay odds are calculated.
Parlay House Edge vs. a Straight Bet: Does It Matter?
On a single −110 straight wager the house edge is roughly 4.5%. A two-leg parlay nearly matches that, but every additional leg drives the margin further above what a sequence of straight bets would cost you in aggregate. If expected value matters to your bankroll strategy, the comparison between parlays and straight bets lays out exactly where each wager type wins and loses.
Do Leg Types Change the Edge?
Yes — the vig embedded in each leg's price drives the calculation. Adding a heavy favorite priced at −300 inflates the implied probability far above 50%, compressing your potential payout and widening the house edge faster than a −110 leg would. Understanding what types of legs — spreads, moneylines, totals — belong on a parlay ticket helps you manage how much edge you hand the book before the game even starts.
Same-game parlays can introduce additional correlation restrictions; the book may adjust payouts on legs it deems correlated. Learn more about those mechanics on the same-game parlay page.
Can Promotions Offset the Compounding Edge?
Partially. Parlay boosts and parlay insurance refunds trim the effective edge on specific tickets, but they don't eliminate compounding — they apply one-time benefits to individual wagers. Wagering requirements on bonus bets can also reduce the net value; the playthrough rules on parlay bonuses explain how those terms further affect your return.
The Bottom Line on Parlay Vig
The parlay house edge is the single most important number to understand before you build a multi-leg ticket. At two legs the cost is moderate; by five legs you are working against a margin comparable to some of the worst bets in a casino. That does not mean parlays are irrational — large payouts from small stakes have obvious appeal — but you should enter every ticket knowing the math. The full overview at parlay odds and payout tables ties all of this together in one place.
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