American odds use a plus or minus sign — plus numbers show how much you win on a $100 bet, minus numbers show how much you need to risk to win $100.
Every American betting line starts with either a + or a − followed by a number. Those two pieces of information tell you everything about the bet's cost and payout. A minus number is a favorite. -200 means you risk $200 to win $100. A plus number is an underdog. +180 means a $100 bet returns $180 in profit. The bigger the number in either direction, the more lopsided the market sees the matchup. The second thing to notice: the gap between the favorite's price and the underdog's price is the juice. If the favorite is -150 and the underdog is +130, that 20-point spread between them is the book's margin on the market.
Example
You see Celtics -220, Raptors +180 on the moneyline. A $22 bet on Boston would pay $10 in profit if they win. A $20 bet on Toronto would pay $36 in profit if they win. The Celtics are heavier favorites because their number is further from zero on the minus side.
What it means for your decision
Reading odds is about seeing past the numbers to what the market is implying. Convert them into probabilities in your head — a -200 favorite is saying the team wins about 67% of the time before juice. If your own read differs meaningfully from that, you've found a place worth examining. Your decision is always yours.
Frequently asked
What do decimal odds mean?
Decimal odds (used in Europe and Australia) show your total payout per $1 including your stake. 2.00 means you double your money.
How do fractional odds work?
Fractional odds (used in the UK) show profit over stake as a fraction. 5/2 means you win $5 for every $2 risked.
What does a short line or long line mean?
A short line is close to even money (-120 vs +100). A long line means big gaps (-400 vs +310) — the market sees a big talent difference.
Is it harder to win betting favorites or underdogs?
Neither, from a math standpoint. Favorites win more often, underdogs pay more when they do — profitability comes from finding mispriced games, not from preferring one side.
Related terms
In the glossary