Teacher's Bet.

Parlay Calculator

A parlay ties several bets into one: every leg has to win, and the odds multiply. Enter your legs below and the combined odds, payout, and — the number the sportsbook hopes you never work out — the true break-even chance are computed live, every step shown.

Parlays are the classic −EV trap — see the full breakdown in Betting Mistakes →

How a parlay is priced

Convert each leg to decimal odds (what $1 returns, stake included), then multiply. That product is the combined decimal odds; times your stake is the payout:

The break-even chance — how often the ticket must hit just to not lose money — is the reciprocal, which equals the product of every leg’s implied probability:

Why the house loves parlays

Every posted price carries the book’s cut (the vig). One −110 leg holds about 4.5%. Multiply the legs and you multiply the margins — the parlay’s hold balloons to something no single bet would ever charge. That’s the whole trick: a parlay lets the book collect its edge once per leg, compounded, on a single ticket.

Worked example

Three −110 legs, $100 stake. Each −110 is decimal 1.909 and implies a 52.4% chance.
Now suppose each leg is really a coin flip (50%). The parlay’s true chance is 0.5³ = 12.5%, so its expected value is 0.125 × 6.96 − 1 = −13%. A single −110 coin-flip leg is only −4.5%. Stacking three of them nearly tripled the expected loss — that’s the compounded vig, in one number.

The honest use of a parlay is the reverse: if you genuinely have an edge on independent legs, tying them multiplies the edge too. Enter your real win chance above and the calculator shows whether the ticket clears zero. To size any bet you like, use the Kelly calculator; to check a single leg, the +EV calculator. The full trap is walked through in Betting Mistakes.

Frequently asked questions

How does a parlay calculator work?

It converts each leg’s American odds to decimal odds, multiplies them into one combined number, and multiplies that by your stake for the payout. Every leg must win; a single loss loses the whole ticket. It also shows the combined American odds and the break-even chance — the product of every leg’s implied probability.

Why are parlays a bad bet?

Because the vig compounds. Each leg’s price already carries the book’s margin, and multiplying the legs multiplies the margins. Three −110 legs each hold about 4.5%, but the parlay holds roughly 13% — you pay the house edge once per leg, all at once. That’s why parlays are the most profitable product on a sportsbook’s menu.

What are the odds of a parlay hitting?

The break-even chance is the product of every leg’s implied probability. Three −110 legs (each about 52.4%) come to about 14.4%. Add legs and it collapses fast: a five-leg parlay of −110s breaks even under 4% of the time.

How is a parlay payout calculated?

Multiply the decimal odds of every leg to get the combined decimal odds, then multiply by your stake. A $100 three-leg parlay of −110s pays 1.909 × 1.909 × 1.909 = 6.96 times your stake — about $696 back for $100 risked.