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Parlay EV Calculator
Compound probability times compound payout minus stake. Add legs with American odds and your model's true probability — see parlay EV, leg-by-leg edges, and the break-even probability for the combined bet.
Parlay EV Calculator
Estimate payout, probability, and expected value across legs. Add optional game or player IDs to catch same-game and same-player correlation risk.
Independent product is only a baseline. Same-game and same-player legs are dependent: depending on the legs, the real parlay probability can be higher or lower than the naive product, and this page has no fitted model to say which.
Why parlays are -EV at standard prices
At true 50/50 win probabilities and -110 prices, expected loss is 4.55% for one leg, 8.88% for two legs, and 13.0% for three legs. Three -110 legs pay 6.96 decimal (+596 American) against the fair 8.00 decimal price for a 12.5% outcome.
A positive calculated EV depends on the entered probabilities and the offered payout. Dependence between legs can change the combined probability in either direction. This page shows an illustrative scenario for related legs and does not establish their true probability.
Recommended workflow
- Use the No Vig Calculator to get a fair probability for each leg from the book's odds.
- Adjust each leg's "Your true prob" if your own model disagrees with the market — even 1 point of disagreement compounds across legs.
- Read each leg’s probability and price, then compare the combined estimate with the independent baseline. Small changes in an input can change the result.
- Explore the stake formula in the Kelly Calculator with the entered parlay probability and combined decimal odds.
FAQ
What does the parlay estimate describe?
The estimate depends on the entered probabilities, payout and dependence between legs. For independent 50/50 legs priced at -110, a three-leg ticket has a calculated expected loss of 13.0% of stake. A positive calculated EV is conditional on those inputs; it does not predict a return.
What does "correlated parlay" mean?
Two legs are correlated when the outcome of one shifts the probability of the other. Classic example: betting the over on team total points and the over on game total — if team A scores more, the game total is more likely to also go over. Books reject many same-game parlays for this reason, or price the multiplier lower than the product of leg odds. Legs that share a game or player ID switch the EV to a conservative haircut scenario (dependence can push the real probability either way, and this page has no fitted model); with no shared IDs, legs are treated as independent and the page says "no correlation applied."
How is parlay EV calculated?
For independent legs: parlay_prob = Π(leg_prob_i); payout_multiplier = Π(decimal_odds_i); win_payout = stake × payout_multiplier; EV = parlay_prob × win_payout − stake. The win payout includes the returned stake. The table compares each entered probability with the offered odds and reports each leg's calculated EV; the combined EV incorporates every leg.
Why can the scenario EV differ from the individual leg estimates?
For independent legs at the displayed product payout, it should not: each leg has an expected-return factor of true probability × decimal odds, and multiplying factors above 1 stays above 1. A negative scenario EV means shared game or player IDs triggered the illustrative correlation haircut, or at least one displayed leg has a non-positive calculated EV at its entered probability and price.
Should I round-robin instead of parlay?
Round-robins (a set of smaller parlays from a pool of legs) reduce variance but not vig — the round-robin's EV is the average of the constituent parlay EVs, weighted by stake. If each constituent is -EV, the round-robin is -EV. The calculator reports each constituent parlay's estimated EV so you can compare the structures.
The cumulative-EV curve shows how expected value changes as each leg is added.
Devig the book to get fair probability — use as input to each parlay leg.
Compare full and fractional Kelly calculations for the entered probability and price.