Parlay Probability Visualizer

See exactly how parlay probability drops exponentially as you add legs. Interactive chart reveals why sportsbooks love parlays, and why most bettors lose.

Presets

Configure Visualization

Win Probability Per Leg 55.0%

True probability each leg wins

Number of Legs 10

legs

Maximum legs to visualize (2–15)

Stake Amount

Amount wagered on the parlay

Probability vs. Payout

Win Probability (%)

Payout Multiplier (x)

Detailed Breakdown

Legs	Win Prob	Chance of Losing	Payout Mult.	Expected Payout on $10	EV per $1	House Edge
2	30.25%	-45.0%	3.01x	$9.11	-$0.0888	8.88%
3	16.64%	-69.8%	5.23x	$8.70	-$0.1303	13.03%
4	9.15%	-83.4%	9.07x	$8.30	-$0.1698	16.98%
5	5.03%	-90.8%	15.75x	$7.92	-$0.2075	20.75%
6	2.77%	-95.0%	27.33x	$7.56	-$0.2436	24.36%
7	1.52%	-97.2%	47.43x	$7.22	-$0.2779	27.79%
8	0.84%	-98.5%	82.31x	$6.89	-$0.3108	31.08%
9	0.46%	-99.2%	142.86x	$6.58	-$0.3421	34.21%
10	0.25%	-99.5%	247.94x	$6.28	-$0.3720	37.20%

Leg-by-Leg Probability Drop

Each bar shows how probability cascades downward as legs are added. There is no weakest leg to find: under this model each added leg costs vig x (1 minus vig) of the remaining value, which is strictly smaller every time. The first leg you add is the most expensive one, and each one after costs less than the last.

30.3%

2-leg-45%

16.6%

3-leg-70%

9.2%

4-leg-83%

5.0%

5-leg-91%

2.8%

6-leg-95%

1.5%

7-leg-97%

0.8%

8-leg-98%

0.5%

9-leg-99%

0.3%

10-leg-100%

10-Leg Parlay: The Illusion

Payout248x

Win Rate0.25%

Hit Frequency1 in 395

A 10-leg parlay at 55% per leg pays 248x, but you only win 0.25% of the time: about 1 in every 395 attempts. At 248x you would need to hit 1 in 248 just to break even.

Net EV is Always Negative

EV on $10 (2-leg)-$0.89

EV on $10 (5-leg)-$2.08

EV on $10 (10-leg)-$3.72

Standard sportsbook odds include ~4.5% vig per leg. Each additional leg compounds the house edge, making longer parlays progressively worse bets. A 10-leg parlay has roughly 37.2% total house edge.

Parlay Types

All legs from a single game
Advantage: Legs can be correlated (e.g., team to win + over on total)
Disadvantage: Sportsbooks adjust odds to account for correlation, often adding extra vig
Correlation can work in your favor if the book underestimates it
Typically limited to 4–8 legs by sportsbooks

Legs from different games/events
Advantage: Legs are truly independent, no hidden correlation
Disadvantage: No correlation edge to exploit; pure probability multiplication
More legs available (up to 15+) but each compounds the house edge
Higher variance, lower expected value

Independent: Outcomes do not affect each other (NBA game + NFL game)
Correlated: Outcomes are linked (team points + game total in same game)
Positive correlation means if one hits, the other is more likely
Negative correlation means if one hits, the other is less likely
Smart bettors look for positively correlated legs that sportsbooks underprice

Break-Even Analysis

What hit rate does each parlay size need to break even? At -110 a leg the answer per leg is 52.38%, and it is the same at every length: the payouts compound exactly as fast as the probabilities do. What changes is the overall hit rate you have to sustain, shown against your own rate at 55% a leg.

2-Leg

Hit rate needed27.44%

Yours at 55%30.25%

3-Leg

Hit rate needed14.37%

Yours at 55%16.64%

4-Leg

Hit rate needed7.53%

Yours at 55%9.15%

5-Leg

Hit rate needed3.94%

Yours at 55%5.03%

6-Leg

Hit rate needed2.07%

Yours at 55%2.77%

7-Leg

Hit rate needed1.08%

Yours at 55%1.52%

8-Leg

Hit rate needed0.57%

Yours at 55%0.84%

9-Leg

Hit rate needed0.30%

Yours at 55%0.46%

10-Leg

Hit rate needed0.16%

Yours at 55%0.25%

11-Leg

Hit rate needed0.08%

Yours at 55%0.14%

12-Leg

Hit rate needed0.04%

Yours at 55%0.08%

Understanding Parlay Mathematics

How Parlays Compound Risk

A parlay requires every leg to win. The probability of all legs hitting is the product of each individual probability. With 55% per leg: 2 legs = 30.25%, 3 legs = 16.6%, 5 legs = 5.03%, 10 legs = 0.25%. Each additional leg doesn't just subtract, it multiplies the difficulty. This is why parlays are sometimes called "sucker bets."

Formula

P(parlay) = P(leg1) × P(leg2) × ... × P(legN)P(all win) = p^N (if each leg has same probability p)

Why Sportsbooks Love Parlays

Sportsbooks build a ~4.5% vig (juice) into each leg. On a single bet, the house edge is small. But on a parlay, the vig compounds with every leg. A 2-leg parlay has roughly 9% house edge, a 5-leg has ~21%, and a 10-leg has ~37%. The flashy payout multipliers mask the fact that the true fair payout should be even higher. Sportsbooks earn their highest margins on parlays, it's their most profitable product.

Correlated Parlays

Not all parlay legs are independent. In a same-game parlay, if you bet on a team to win AND the game to go over the total, these are positively correlated. A team blowing out an opponent often means more total points. If the sportsbook prices these legs independently, the true combined probability is higher than the multiplicative estimate, giving you an edge. This is the one scenario where parlays can be +EV.

Optimal Parlay Size

If you must parlay, keep it short. 2–3 leg parlays have the lowest compounded house edge and the highest realistic hit rates. The "sweet spot" for recreational bettors is a 2-leg parlay of positively correlated same-game props. Beyond 4 legs, the math turns heavily against you. Professional bettors almost never play parlays unless they have identified a significant correlation edge that the book has mispriced.

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