Parlay Calculator
Two to six legs in — combined odds, payout, and the true EV of the ticket out.
Your combined edge survives the multiplication — this parlay is priced in your favor.
Worked example
Three legs at −110 each: decimal 1.909 × 1.909 × 1.909 = 6.96, or +596 — a $10 stake pays $69.58. If your fair read on each leg is 52.4% (exactly the implied rate), the true hit rate is 14.4% and the EV is 0.0% before margin — the vig is already priced in against you. Give each leg a real 55% fair instead and the same ticket jumps to +15.8% EV. Parlays don’t create edge; they only multiply whatever edge — or lack of it — the legs already have.
FAQ
How are parlay odds calculated?
Convert each leg to decimal odds and multiply. Two legs at −110 are 1.909 × 1.909 = 3.645 in decimal, which converts back to +264. The payout multiplies the same way your stake does — the stake rides from leg to leg.
Why is the true EV of a parlay usually negative?
The book’s margin multiplies with the legs. At −110 each leg holds about 4.8%, so a two-leg parlay gives up roughly 9% and a four-legger nearly 18%. Unless your fair probabilities beat the implied ones on enough legs, the parlay pays less than the true chance of hitting it.
Does this calculator assume the legs are independent?
Yes. It multiplies your fair probabilities, which is only valid for independent legs. Correlated parlays (same game, related outcomes) price differently — books either block them or shade the price hard — so treat the true-EV number as the independence case.
What does "blank = no edge" mean on a leg?
Leaving a leg’s fair probability empty tells the calculator to use that leg’s implied probability — i.e. to assume the price is fair and you have no opinion. That prices the leg at 0% EV before margin, so the combined EV shows you exactly what the vig costs across the whole ticket.
When is a parlay actually +EV?
When enough legs are individually +EV. Edges multiply too: three legs each priced 5% in your favor compound to roughly 16% combined. If you wouldn’t bet every leg straight, the math rarely rescues the parlay.
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