Why do parlays pay so much and win so rarely?

Q: Why do parlays pay so much and win so rarely?

A parlay requires every leg to win, so the payouts multiply, but so does the sportsbook's margin. Each -110 leg carries about a 4.55% hold, and stacking legs compounds it: roughly 8.9% on two legs, 13.0% on three, 17.0% on four, and 20.7% on five. The big advertised payout is the visible part; the compounded vig is the part that isn't.

Bet Types

4 diagrams•5 min read•Updated Aug 17, 2026

Written by VIMB

Short answer

Parlays aren't a scam. They're the same bets with the house edge charged once per leg. Every leg you add roughly doubles down on the vig.

A parlay combines several bets into one ticket. Every leg has to win or the whole thing loses. In exchange, the payouts multiply rather than add, which is exactly why they're the most heavily marketed product on every sportsbook app.

Where the payout comes from

The math is simple multiplication in decimal odds. A -110 bet is 1.909 in decimal. Two of them parlayed is 1.909 × 1.909 = 3.645, which is about +264.

Now compare that to what a fair payout would be. Strip the vig and each -110 leg is really a 50% proposition. Two independent 50% events both hitting is 25%, a fair price of +300. The book pays +264. The gap is the vig, charged twice.

How often every leg landsProbability all legs win, at a fair 50% per leg.

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The vig compoundsTheoretical hold on a parlay of -110 legs.

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Legs	Parlay price	Fair (no-vig) price	Theoretical hold
1	-110	+100	4.5%
2	+264	+300	8.9%
3	+596	+700	13.0%
4	+1228	+1500	17.0%
5	+2436	+3100	20.7%
6	+4741	+6300	24.4%

Hold on n legs = 1 − 0.9545ⁿ

Each -110 leg keeps 4.55%; the survivors of each leg get charged again on the next one.

Paid vs. fairWhat the ticket returns, against what those odds are worth.

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Same-game parlays are a different animal

Legs from the same game aren't independent. A quarterback throwing for 350 yards makes his receiver's yardage prop far more likely. Books price same-game parlays with a correlation model rather than by plain multiplication, and that model is where additional margin lives. Never assume an SGP price is 'the legs multiplied'.

Why same-game legs are differentIndependent legs multiply. Correlated legs don't.

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The honest framing

A parlay is not a mistake if you know what you're buying: a low-probability, high-variance ticket at a worse price than the legs deserve. It stops being defensible when it's your main strategy and you believe the payout reflects the risk.

If you're going to bet them anyway

▸Fewer legs. Every leg added compounds the margin against you.

▸Shop the legs individually first. A parlay of bad prices is a very expensive way to be wrong.

▸Treat promos and boosts as what changes the math, not the number of legs.

▸Size them as entertainment money, not as bankroll strategy.