How Do Betting Odds Work? Reading the Numbers, the Payout and the Vig

Betting odds do two jobs at once. They tell you how much a bet pays if it wins, and they show how likely the sportsbook thinks that result is. In the US you'll see them as American odds like -150 or +130: the minus number is what you risk to win $100, and the plus number is what a $100 bet wins.

Everything else, from decimal and fractional odds to the vig and implied probability, is a different way of saying those same two things. Once you can read one price, you can read them all. We'll go through each piece with real numbers, and link to the deeper guides as we go.

What the odds on a betting line are telling you

Every price on a sportsbook's board answers one question: if I bet this and it wins, how much do I get? A bettor looking at a game sees three things on the betting line: the point spread, the total (over/under) and the moneyline. Each of them carries a price.

Take a typical NFL game. The Eagles are -150 on the moneyline and the Cowboys are +130. That tells you the Eagles are the favorite (the minus sign) and the Cowboys are the underdog (the plus sign). It also tells you exactly what each side pays. A $150 bet on the Eagles wins $100. A $100 bet on the Cowboys wins $130.

Notice the favorite pays less than you risk and the underdog pays more. That's the whole idea of odds. The more likely something is, the less it pays.

American odds: the plus and minus signs

American odds (also called moneyline odds or Vegas odds) are built around $100. It's the format every US sportsbook and sports betting app uses, and it's the one you'll bet with on Paid2Bet.

Negative odds are for favorites. The number shows how much you have to bet to win $100. At -200 you risk $200 to win $100. At -110, the price on most spreads and totals, you risk $110 to win $100. We go through that one in detail in what -110 means in betting.

Positive odds are for underdogs. The number shows how much a $100 bet wins. At +150 a $100 bet wins $150; at +200 it wins $200. The +150 guide walks through that price at every stake.

You don't have to bet $100, of course. The math scales. A $10 bet at +150 wins $15, and a $10 bet at -200 wins $5. If you'd like the full walk-through with practice examples, start with how to read American odds.

One odd case: +100 and -100 mean the same thing. That's even money, or even odds, where you win exactly what you risk.

Decimal odds

Decimal odds are the format used in Europe, Canada and Australia, which is why you'll sometimes hear them called European odds. They're the simplest of the three to use. Multiply your stake by the decimal number and you get your total payout, stake included.

So 2.50 means a $10 bet returns $25: your $10 back plus $15 profit. 1.91 means a $10 bet returns $19.10. Anything above 2.00 is an underdog price, and anything below 2.00 is a favorite. Exactly 2.00 is even money.

The catch for US bettors is that decimal odds include the stake and American odds don't, so the numbers don't line up the way you'd expect. 2.50 is +150, not +250. There's a table and the formulas in converting decimal odds to American odds.

Fractional odds

Fractional odds are the traditional British odds, still common in horse racing and at UK bookmakers. They read as profit over stake. 3/1 (said "three to one") means you win $3 for every $1 you bet. 1/2 means you win $1 for every $2. You always get your stake back on top.

That's how the old "7 to 1" and "11 to 2" phrases work. 7/1 is +700: a $10 bet wins $70. 11/2 is +550: a $2 bet wins $11, so a $10 bet wins $55. When the first number is bigger, it's an underdog. When it's smaller, like 1/2, it's a favorite. Our guide to fractional odds has the rest, including the odd ones like 5/4 and 10/11.

The same bet in all three formats

Here are a few common prices side by side. They're the same bets, just written differently.

How to work out a payout from the odds

There are only two formulas, one for each sign. With positive odds, profit = stake × (odds ÷ 100). With negative odds, profit = stake × (100 ÷ the odds without the minus sign). Add your stake to the profit and you have the total payout.

Say you bet $20 on the Cowboys at +130. That's $20 × 1.30 = $26 profit, and $46 back in total. Bet $30 on the Eagles at -150 instead and it's $30 × (100 ÷ 150) = $20 profit, $50 back.

Profit versus total payout is where most people get mixed up. A bet slip's "potential payout" or "to return" usually includes your stake. "To win" is the profit alone. Check which one you're looking at before you decide a price is worth it.

Odds and implied probability

Every price can be turned into a percentage: the chance the sportsbook is giving that result. That's implied probability, and it's the most useful thing you can learn to calculate.

For a minus price, divide the odds by the odds plus 100. -150 becomes 150 ÷ 250 = 60%. For a plus price, divide 100 by the odds plus 100. +130 becomes 100 ÷ 230 = 43.5%. With decimal odds it's even easier: 1 ÷ 2.50 = 40%.

Why care? Because it turns "is this a good bet?" into a question you can answer. If you think the Cowboys win this game half the time, +130 is a good price, since the odds only give them 43.5%. If you think they win a third of the time, it's a bad one, no matter how nice the payout looks. There's more on this, including how to strip the book's cut out of the numbers, in implied probability in betting.

The vig: how sportsbooks make money from the odds

Add up the implied chances on both sides of our Eagles-Cowboys game: 60% plus 43.5% is 103.5%. Real probabilities add up to 100%. The extra 3.5% is the sportsbook's margin, called the vig or the juice.

It's easiest to see on a spread. Both sides are usually -110, which works out to 52.4% each, or 104.8% together. If two people bet $110 each on opposite sides, the book takes in $220 and pays the winner $210. It keeps $10 whatever happens.

That's also why you need to win more than half your bets to make money. At -110 the break-even point is 52.4%. Going 50-50 loses a little every week, and that's the hardest thing for new bettors to accept.

Odds on different types of bets

The odds work the same way whatever you bet. What changes is the question the bet asks.

On a moneyline bet you just pick the winner, so the prices spread out with the matchup: -400 on a big favorite, +320 on the long shot. On a point spread bet, the favorite gives points and the underdog gets them, so the two sides are close to even and both are usually priced around -110. Totals (over/under) work the same way on the combined score. If those are new, our guide to straight bets covers spreads, moneylines and totals one at a time.

Player props, period lines and futures all use the same American odds. A prop on a quarterback's passing yards might be -115 on the over and -105 on the under. A preseason title future might be +900.

Parlays are where odds get interesting, because the legs multiply. Three -110 legs together pay about 6 to 1, not 3 to 1. We explain the math in what a parlay is and how to calculate a parlay payout.

Why betting odds change

Odds aren't fixed. A sportsbook opens a betting market with a number and then moves it. Heavy money on one side pushes its price up (more negative) and the other side's price down. News moves lines too: a starting quarterback ruled out, a pitcher scratched, wind at an outdoor game. Sometimes the book just thinks its opening number was off.

The price you get is the one on your bet slip when you place the bet. If the line moves after that, your bet keeps its original odds. That's why people who bet early on a number they like sometimes look smart by game time, and sometimes don't.

Practice reading odds with a free balance

You'll learn this faster by doing it than by reading about it. On Paid2Bet you get a free balance to bet with, no deposit and no credit card, and bets start at five cents. Pick a game on the NFL board, look at the moneyline, the spread and the total, and work out what each pays before the slip tells you. If you want a second opinion first, the consensus picks show which side other players are on.

Do that a dozen times and the numbers stop looking like a foreign language.

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