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American odds in · updates as you type · nothing is saved.
PAR
Parlay
Add a leg per pick, enter each price in American odds, set your stake. The combined odds, the chance every leg hits, and the payout update as you type.
| American odds | Decimal |
|---|
Stake
$
Combined odds—
Decimal—
Implied probability—
Payout—
Profit—
How parlay odds work
Each leg's American price becomes a decimal (−110 becomes 1.909), the
decimals multiply, and the product converts back to American. The implied probability is
1 ÷ the combined decimal — the chance all legs hit if the price were fair. One
losing leg loses the whole ticket.
EV
Expected value
Enter a price, your own fair chance the bet wins, and a stake. See whether the number beats the price — and by how much per dollar.
American odds
Fair win %
Stake$
The fair win % is the one input we can't give you — take it from a de-vigged sharp line, a model, or the no-vig consensus across books.
Enter odds, a fair win %, and a stake
Expected value—
EV %—
Implied book %—
Decimal odds—
What the number means
EV = your win chance × profit if it hits − your lose
chance × stake. Positive means the price is generous relative to the true odds; over
many bets that gap is your edge. EV % is that per dollar staked. It says nothing
about any single bet — a +5% bet still loses most of the time at short odds.
ARB
Arbitrage
Put the best price you can get on each outcome, from any books. If the combined implied probability is under 100%, backing all sides locks a profit.
Market
Outcome 1
Outcome 2
Outcome 3
Total stake
$
Enter a price for every outcome
Total implied—
Profit %—
Guaranteed profit—
How the split works
Each price becomes an implied probability (1 ÷ decimal). Add them: under
100% and there's room. The stake is divided in proportion to those probabilities so every
outcome returns the same amount — and that amount is more than the total you put down.
Books limit accounts that do this consistently.
FAQ
Questions
How are parlay odds calculated?
Every leg's American price is turned into decimal odds, the decimals are multiplied together, and the product is converted back to American. The implied probability is 1 divided by that combined decimal.
What is expected value?
Expected value is what a bet is worth on average: your fair chance to win times the profit if it hits, minus your chance to lose times the stake. Positive EV means the price is better than the true odds.
How do I get the fair win %?
Strip the vig from a sharp book's two-way market, use a model, or use the consensus no-vig line across several books. It is the one number you have to supply — the calculator can't know it.
What is an arbitrage bet?
Backing every outcome of a market at different books so the combined implied probability is under 100%. The stake is split so every result pays the same, and that amount is more than you put in.
Will sportsbooks limit me for arbitrage?
They can and do. Arbing, steady +EV betting and heavy line-shopping all draw limits over time. These tools do the math; managing that risk is on you.
Analysis only · not gambling advice · 21+
Tonight's card · Track record · Learn · How it works · @PropsEdgeBTN · Privacy Policy · Terms of Service · If gambling is a problem, call 1-800-GAMBLER
Tonight's card · Track record · Learn · How it works · @PropsEdgeBTN · Privacy Policy · Terms of Service · If gambling is a problem, call 1-800-GAMBLER