The 30-second version
American odds answer one question: how much do I win relative to $100? Negative odds (-110, -200) tell you how much you must risk to win $100. Positive odds (+150, +300) tell you how much you win if you risk $100. That's the whole system.
So -110 means risk $110 to win $100. +150 means risk $100 to win $150. A -200 favorite means the book thinks that side wins a lot more often than not — you're paying a premium price for a likely outcome.
Odds are really probabilities in disguise
Every price converts to an implied win probability. For negative odds: probability = odds / (odds + 100), using the odds as a positive number. So -110 implies 110/210 = 52.4%, and -200 implies 200/300 = 66.7%. For positive odds: probability = 100 / (odds + 100). So +150 implies 100/250 = 40%, and +300 implies 25%.
This is a useful conversion, but the result is a vig-included price-implied break-even rate, not a verified market forecast. At +150, the listed price implies a 40% break-even rate before any adjustment for margin. The relevant comparison is between that price-implied rate and a defensible probability estimate with its uncertainty made explicit.
Why both sides are -110: the vig
A fair coin flip should be +100 both ways. Sportsbooks post -110/-110 instead. Add the implied probabilities: 52.4% + 52.4% = 104.8%. That extra 4.8% is the vig (or juice) — the book's built-in fee. It means a spread bettor must win about 52.4% of the time just to break even, not 50%.
The vig is why picking more winners than losers isn't enough to profit, and why line shopping matters: getting -105 instead of -110 sounds trivial but cuts the tax you pay on every single bet.
Reading a real board
Take an MLB game: Yankees -160, Rays +140. Those prices imply 61.5% and 41.7%, which add to more than 100% because of margin. A proportional no-vig normalization is roughly 60/40, but that convention is not a verified true probability.
If a bettor assumes the Rays win 45% of the time, +140 (41.7% price-implied) produces positive expected value under that assumption even though the Rays would still lose more often than win. The conclusion depends on the estimate and exact price being accurate; it is not a recommendation or guaranteed edge.
Frequently asked questions
What does -110 mean in betting?
You must risk $110 to win $100. It implies a 52.4% probability and includes the sportsbook's fee (the vig).
Is + or - better in betting odds?
Neither is inherently better. The sign describes payout and break-even rate, not whether a wager is favorable. Any value estimate depends on comparing the vig-included price with a defensible probability estimate and its uncertainty.
How do I convert American odds to probability?
Negative odds: odds/(odds+100) using the absolute value, so -150 → 150/250 = 60%. Positive odds: 100/(odds+100), so +200 → 100/300 = 33.3%.
Available released picks include their posted price and, after settlement, an outcome receipt. Check featured-pick availability.
Keep reading
Expected value combines a stated win-probability assumption with a quoted payout. Learn the arithmetic, the break-even comparison, and why the result is not a guarantee.
What a betting unit is, how to choose a conservative personal unit, and why fixed limits matter more than promotional performance claims.
Closing line value compares the price you took with the closing price. Learn how to calculate it, what it can indicate, and why it does not guarantee profit.