A parlay wins only if every leg wins, so the probability is the legs multiplied together. With independent coin-flip legs, a two-leg parlay wins 25.0% of the time, three legs 12.5%, four legs 6.25% and ten legs 0.098%. The price paid is always shorter than those odds.
Build any combination in the parlay calculator.
The exact answer, by number of legs
A parlay wins only if every leg wins. If the legs are independent, the chance of that is the product of their individual chances. A point spread or total priced −110 on both sides is a coin flip by construction — the two sides cannot both be better than even — so the clean case is 50% per leg.
| Legs | Win probability | Roughly | Price at −110 legs | Break-even rate |
|---|---|---|---|---|
| 2 | 25.00% | 1 in 4 | +264 | 27.44% |
| 3 | 12.50% | 1 in 8 | +596 | 14.37% |
| 4 | 6.25% | 1 in 16 | +1228 | 7.53% |
| 5 | 3.12% | 1 in 32 | +2436 | 3.94% |
| 6 | 1.56% | 1 in 64 | +4741 | 2.07% |
| 7 | 0.781% | 1 in 128 | +9142 | 1.08% |
| 8 | 0.391% | 1 in 256 | +17545 | 0.567% |
| 9 | 0.195% | 1 in 512 | +33585 | 0.297% |
| 10 | 0.098% | 1 in 1,024 | +64208 | 0.156% |
| 11 | 0.049% | 1 in 2,048 | +122670 | 0.081% |
| 12 | 0.024% | 1 in 4,096 | +234279 | 0.043% |
Win probability assumes independent 50/50 legs. Break-even rate is the implied probability of the offered price — the hit rate needed to come out level.
Read the last two columns together. A four-leg parlay wins 6.25% of the time and is priced to break even at 7.53%. The gap between those two columns is the sportsbook's margin, and it compounds with every leg added.
What the parlay pays
| Legs | Decimal price | American price | Implied probability | $10 returns |
|---|---|---|---|---|
| 2 | 3.64 | +264 | 27.44% | $36.45 |
| 3 | 6.96 | +596 | 14.37% | $69.58 |
| 4 | 13.28 | +1228 | 7.53% | $132.83 |
| 5 | 25.36 | +2436 | 3.94% | $253.59 |
| 6 | 48.41 | +4741 | 2.07% | $484.13 |
| 7 | 92.42 | +9142 | 1.08% | $924.24 |
| 8 | 176.45 | +17545 | 0.57% | $1,764.46 |
| 9 | 336.85 | +33585 | 0.30% | $3,368.52 |
| 10 | 643.08 | +64208 | 0.16% | $6,430.82 |
| 11 | 1,227.70 | +122670 | 0.08% | $12,277.01 |
| 12 | 2,343.79 | +234279 | 0.04% | $23,437.93 |
Every leg priced −110. Decimal price is 1.9091 raised to the number of legs; the return column includes the returned stake.
The same parlay with no margin at all
Price the identical legs at even money (+100) instead of −110 and the arithmetic becomes the clean power of two. This is the useful comparison, because the difference between the two tables is the margin — nothing else changes.
| Legs | Decimal price | American price | Implied probability | $10 returns |
|---|---|---|---|---|
| 2 | 4.00 | +300 | 25.00% | $40.00 |
| 3 | 8.00 | +700 | 12.50% | $80.00 |
| 4 | 16.00 | +1500 | 6.25% | $160.00 |
| 5 | 32.00 | +3100 | 3.13% | $320.00 |
| 6 | 64.00 | +6300 | 1.56% | $640.00 |
| 7 | 128.00 | +12700 | 0.78% | $1,280.00 |
| 8 | 256.00 | +25500 | 0.39% | $2,560.00 |
| 9 | 512.00 | +51100 | 0.20% | $5,120.00 |
| 10 | 1,024.00 | +102300 | 0.10% | $10,240.00 |
| 11 | 2,048.00 | +204700 | 0.05% | $20,480.00 |
| 12 | 4,096.00 | +409500 | 0.02% | $40,960.00 |
Every leg priced +100. At this price the implied probability equals the true probability of independent coin-flip legs, so the break-even rate and the win rate are the same number and the bet is a fair one.
A five-leg parlay of coin flips is worth +3100 at a fair price. Priced with standard −110 legs it pays +2436 — a $10 stake returns $253.59 instead of $320.00.
Do real legs behave like coin flips?
For standard-priced spreads, close to it — and that is measurable rather than assumed. Across 1,693 NFL games in our archive, the home side covered 827 times, the away side 825 times, and 41 games pushed. That is what a market with no systematic tilt looks like.
The favorite-versus-underdog split is the same story: favorites covered 48.97% of decided games across 1,687 games with a usable spread. We publish that broken out by price band.
One important caveat runs the other way: legs inside a parlay are frequently not independent. Same-game legs are correlated by design, and sportsbooks price same-game parlays to account for that. The table above describes independent legs.
Why our own graded record is not used here
Nebula Insights keeps a public, immutable record of every projection it publishes, logged before the game and graded after it. That record is deliberately not the source of the leg rate above, for two reasons: a graded projection is a statement about a number, not a wager settled at a price, so it is not a bet leg; and the log is young. The market-wide archive measurement is the right instrument for this question. The projection record is published in full on the track record page with its own counts.
What a push does to a parlay
A pushed leg is normally removed and the parlay re-prices as if it had one fewer leg. That is neither a win nor a loss on that leg. Since 2.42% of NFL spread bets pushed in our sample, a multi-leg NFL parlay meets a push reasonably often. House rules on this vary — check yours.
Where the long-shot parlays land
At twelve legs the arithmetic becomes stark: 0.024%, or about 1 in 4,096, priced at +234279. Nothing about that is hidden; it is the price multiplied out.
How this was measured
- Parlay probabilities and prices come from exact decimal arithmetic in
repo_check/seo/f31_parlay_math.py— no rounding is carried between steps, and American prices are rounded only at display. - Empirical leg behaviour comes from our odds archive matched to final results, n = 1,693 NFL games (2020–2025, regular season and playoffs), with the consensus spread taken from at least three books.
- Legs are assumed independent. Same-game parlay legs are correlated and are priced differently by sportsbooks; those are not what this page measures.
- Odds archive current to 2026-07-28. Figures refresh when the source scripts are re-run.
Next steps
Frequently asked questions
What percentage of parlays win?
With independent legs priced −110, 25.0% of two-leg parlays, 12.5% of three-leg parlays and 3.12% of five-leg parlays win.
What are the odds of hitting a 10-leg parlay?
About 1 in 1,024, or 0.098%, if every leg is a coin flip. It is priced +64208.
Why does a parlay pay less than the true odds?
Because each leg is priced with margin built in. A three-leg parlay wins 12.5% of the time but is priced to break even at 14.37%.
What happens if one leg pushes?
The pushed leg usually drops out and the parlay re-prices with one fewer leg. 2.42% of NFL spread bets pushed in our sample. House rules vary.
Related: parlay calculator · parlay odds chart · how to calculate parlay odds · methodology
Every figure on this page is a historical measurement of what already happened, produced by a committed, re-runnable script over our own odds archive. Past frequencies are not forecasts and are not betting advice: Nebula Insights publishes no picks, no selections and no recommended wagers. 18+ only.