Type in any American odds and see exactly what they mean: the implied probability, the decimal equivalent, and what you'd win. This is the same math from Reading Odds in the Ungambled book — now you can play with it.
Negative odds (like −150) mark the favorite. The number is how much you bet to win $100. So −150 means risk $150 to win $100.
Positive odds (like +200) mark the underdog. The number is how much you win on a $100 bet. So +200 means bet $100 to win $200.
You don't have to bet exactly $100 — that's just the reference point. The ratio stays the same at any size, which is what the calculator above shows.
Every price implies a probability — the chance the book is pricing in. Turn the odds into a percentage and you get the implied probability.
Here's the tell that the house takes a cut: a true coin flip should be +100 (50%). But books price both sides around −110, which implies 52.4% each — 104.8% total. That extra 4.8% is the vig, the sportsbook's built-in margin. Hedging is about finding two books whose prices, added up, leave that margin on your side of the table.
You can do all of this by hand — but the Ungambled app reads the odds across every book and shows you the profitable hedges automatically. That's the whole point.
Get Started →For education only. Not financial advice. Sports betting is legal in some U.S. states and in Ontario, and not elsewhere; you must meet the legal age (21+ in most U.S. states, 19+ in Ontario). If betting stops being fun, call or text 1-800-GAMBLER (U.S.) or ConnexOntario 1-866-531-2600.