How to Read American Odds: What +150 and −110 Actually Mean

Minus number: how much you must risk to win $100. Plus number: how much you win by risking $100. That’s the whole code. At −110 you risk $110 to win $100. At +150 you risk $100 to win $150. The minus side is the favorite, the plus side is the underdog, and the size of the number tells you how strongly the book feels about it.

Nobody is born reading this stuff, and the apps don’t exactly teach it — the price sits there like a secret handshake while you’re deciding where your money goes. Two minutes here and you’ll read a board faster than most people who’ve been betting for years, because most of them never learned what the number is actually saying.

The two formulas (you only ever need these)

Every American price converts to an implied probability — the win rate at which the bet exactly breaks even. Drop the sign and use the matching formula:

• Minus odds: probability = odds ÷ (odds + 100). So −150 → 150/250 = 60%.
• Plus odds: probability = 100 ÷ (odds + 100). So +150 → 100/250 = 40%.

That percentage is the real message inside the price. −110 isn’t just a payout ratio — it’s the book telling you this bet needs to win 52.4% of the time before you’re even. Read enough prices as percentages and the board stops being decoration and starts being a list of claims you can argue with.

Why both sides of a coin flip cost −110

Here’s the tell most bettors never notice. A point spread is built to be a 50/50 proposition — so both sides should pay +100. Instead, the board shows −110 on each side. Run the formula: 52.4% + 52.4% = 104.8%. The outcomes of a game can’t add up to more than 100% — the extra 4.8% is the book’s cut, baked directly into the price. It’s called the vig (or juice), and it’s how the book gets paid no matter which side wins.

The number on the board is not the true chance of the bet. It’s the true chance plus the book’s toll. Learning to read odds is really learning to see the toll.

Two doors open the moment you can see it. First: different books charge different tolls on the same bet, and taking the better number every time is the most repeatable edge in betting — what line shopping is worth. Second: when you stack several prices into one ticket, the tolls stack too, which is why parlays quietly become the most expensive bets on the board — the arithmetic is itemized in how much a parlay actually pays.

Reading a real board in ten seconds

• Sign first. Minus = favorite, plus = underdog. Bigger number, stronger opinion.
• Translate to a percentage. −150 means “needs to hit 60% to break even.” Ask yourself if you actually believe that.
• Compare the toll. −105 and −120 are the same bet at different prices. Never assume your app has the good one.

Inside the Lab, every grade comes with the price already translated — what the number implies, how it compares across books, and whether the model’s read clears the break-even bar. The math shown, never just a pick. Options, not parlays: you see the reasoning, you make every call.

The usual word from us: this is research and education, not a promise of profit. 21+, and only ever bet what you can walk away from.

FAQ

What does +150 mean in betting?

Plus odds show the profit on a $100 bet. At +150, a $100 bet wins $150 profit ($250 back total), and a $10 bet wins $15. Plus numbers mark the underdog — the bigger the number, the less likely the book thinks it is, and the more it pays if it happens. +150 implies about a 40% chance.

What does −110 mean in betting?

Minus odds show how much you must risk to win $100. At −110 you risk $110 to win $100 profit, so a $10 bet wins about $9.09. Minus numbers mark the favorite. −110 is the standard price on spreads and totals, and it implies about a 52.4% break-even rate — the extra beyond 50% is the sportsbook’s built-in cut.

How do I convert American odds to probability?

For minus odds: probability = odds ÷ (odds + 100), using the number without the sign — so −150 is 150/250 = 60%. For plus odds: probability = 100 ÷ (odds + 100) — so +150 is 100/250 = 40%. That number is the implied probability: the win rate at which the bet exactly breaks even.

Why are both sides of the same bet −110?

Because the book charges a toll. Two sides of a coin flip should each be +100, but books post both at −110. The implied probabilities then add to about 104.8% instead of 100% — that extra 4.8% is the vig (or juice), the book’s margin for hosting the bet. It’s why breaking even requires winning 52.4% of the time, not 50%.

What does +100 or “even money” mean?

At +100 (also written EV or even), the profit equals the stake: bet $10, win $10. It implies a 50/50 proposition with no house margin on that side. Odds shade from +100 in both directions — favorites go minus, underdogs go plus.