Odds & prices
Plus and minus odds (+ / −)
Neither sign is “better” — they describe the same trade from opposite ends. Minus odds win more often and pay less; plus odds win less often and pay more. What matters is whether the price's implied probability is beatable, not which sign it carries.
Two prices sit at the boundary: +100 and −100 both mean even money, where a $100 bet wins $100.
The rule, in one line each way
Minus is what you risk to win $100. −150 means risk $150 to win $100. Plus is what you win from a $100 risk. +150 means risk $100 to win $150. That is the entire system; everything else is scaling it to your actual stake.
To scale, divide. At −150, a $30 bet wins 30 × (100 ÷ 150) = $20. At +150, a $30 bet wins 30 × (150 ÷ 100) = $45. Your stake always comes back on top of the profit, so those return $50 and $75 respectively.
The $100 in the definition is a unit of measurement, not a required bet size. It exists so that any two prices can be compared on the same scale.
Turning a sign into a probability
This is the step that makes the numbers useful rather than decorative. For a minus price, implied probability = odds ÷ (odds + 100), using the number without its sign: −150 gives 150 ÷ 250 = 60%. For a plus price, implied probability = 100 ÷ (odds + 100): +150 gives 100 ÷ 250 = 40%.
That percentage is the win rate you need just to break even at that price. Beat it and the bet is profitable over time; fall short and no amount of confidence rescues it. It is also inflated by the book's margin, so the true break-even is slightly kinder than the raw number — de-vig the market to see by how much.
How to read a full betting line
A typical line shows three markets per game. The moneyline is a bare price on the winner: Chiefs −180 / Broncos +150. The spread attaches a number to each side with its own price: Chiefs −6.5 (−110) means they must win by 7 or more, and the −110 is what you pay for it. The total does the same for combined points: Over 44.5 (−110).
Read the sign first to know which side is favored, then the number for the size of that favoritism, then the price in brackets for what it costs. A −6.5 spread at −110 and a −6.5 at −120 are the same bet at different costs, and over a season that bracket is where the money quietly goes.
Why the minus side is not the safer bet
A favorite wins more often and pays less; an underdog wins less often and pays more. Sportsbooks set those prices so that, after their margin, neither is systematically better. Backing favorites feels safer and produces more winning tickets, which is exactly why it is a popular way to lose money slowly.
The only question that matters is whether the implied probability is beatable. A −180 favorite that truly wins 70% of the time is a strong bet; a +150 underdog that truly wins 35% is a bad one. The sign tells you nothing about value on its own.
| Price | Meaning | $100 returns | $25 returns | Implied |
|---|---|---|---|---|
| −300 | risk $300 to win $100 | $133.33 | $33.33 | 75.0% |
| −200 | risk $200 to win $100 | $150.00 | $37.50 | 66.7% |
| −150 | risk $150 to win $100 | $166.67 | $41.67 | 60.0% |
| −110 | risk $110 to win $100 | $190.91 | $47.73 | 52.4% |
| +100 | risk $100 to win $100 | $200.00 | $50.00 | 50.0% |
| +150 | $100 wins $150 | $250.00 | $62.50 | 40.0% |
| +250 | $100 wins $250 | $350.00 | $87.50 | 28.6% |
| +500 | $100 wins $500 | $600.00 | $150.00 | 16.7% |
Returns include your stake. Implied probability includes the book's margin, so it overstates the true chance — de-vig the market for the fair number.
The common mistake: treating a big minus number as a sure thing
A −600 favorite is not a lock, it is a price implying about an 86% chance — which means roughly one loss in seven. And because you risk $600 to win $100 there, a single loss wipes out six wins. Heavy favorites are where bankrolls go quietly, not because they lose often, but because the payout leaves no room for the times they do.
Common questions
- What does plus and minus mean in betting odds?
- The minus sign marks the favorite and shows what you must risk to win $100 (−150 = risk $150 to win $100). The plus sign marks the underdog and shows what a $100 bet wins (+150 = win $150). Your stake is returned on top of the profit either way.
- How do you read American odds?
- Read the sign for which side is favored, the number for how strongly, and the price in brackets for what it costs. Convert to a probability to judge it: minus prices are odds ÷ (odds + 100), plus prices are 100 ÷ (odds + 100). That percentage is the win rate you need to break even.
- Is it better to bet plus or minus odds?
- Neither, inherently. Minus odds win more often and pay less; plus odds win less often and pay more, and books price them so that after their margin neither is systematically better. What matters is whether the true probability beats the price's implied probability.
- What is the difference between +200 and −200?
- They are opposite ends of the same market. At +200 a $100 bet wins $200 and the price implies a 33.3% chance. At −200 you risk $200 to win $100 and it implies 66.7%. One is the underdog, the other the favorite, in roughly a 2-to-1 matchup.
See these numbers on your own bets
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