Compute combined American odds, decimal odds, payout, and parlay probability for 2-6 leg parlays. Most retail parlays are -EV due to compounded vig and correlation; this calculator shows you the math.
Compute combined American odds, decimal odds, payout, and (if probabilities provided) parlay EV for 2-6 leg parlays. Add a leg by entering its odds; leave a leg blank to skip it.
Combined parlay probability (assuming each leg is independent and priced at its implied probability): --. True parlay probability is usually LOWER than this because legs are often correlated (same-game props especially).
A parlay combines multiple bets into one ticket. All legs must win for the parlay to cash. The payout multiplies across all legs, so combined odds are large. But the probability of all legs hitting is the product of each leg's probability, which is small.
For a 2-leg parlay at -110 each: decimal odds 1.909 × 1.909 = 3.64. American: +264. On a $100 stake, profit is $264. Implied probability of both legs hitting at 52.4% each: 27.5%. So a $100 stake to win $264 at 27.5% true probability has the same EV as 100 × (3.64 × 0.275 - 1) = $0.10. Essentially breakeven before correlation effects make it worse.
Three reasons retail parlays lose money long-term:
Rare. Two cases:
In both cases, the math has to be checked per-parlay. Default assumption: retail parlays are -EV. See are MLB parlays profitable for the full breakdown.
Sharp bettors place single bets sized by Kelly fraction, not parlays. The math is cleaner, the vig is lower, and the variance is more predictable. Use the Kelly calculator for single-bet sizing.