How to Read Sports Betting Odds (2025 Beginner Guide)

New to sports betting? Odds look confusing at first but follow simple math. This guide explains every format with real examples so you'll understand every bet before you place it.

Sports betting odds tell you two things: who the sportsbook thinks will win, and how much you'll win if you're right. Once you understand the math behind them, reading odds becomes second nature.

American Odds (Moneyline)

American odds are what you'll see on US sportsbooks like DraftKings and FanDuel. They use a plus (+) or minus (−) sign.

Minus odds (favorites): The number tells you how much you need to bet to win $100.

Example: Chiefs −150 means you bet $150 to win $100 profit. Total return: $250 ($150 stake + $100 profit).

Plus odds (underdogs): The number tells you how much you win on a $100 bet.

Example: Eagles +130 means you bet $100 to win $130 profit. Total return: $230 ($100 stake + $130 profit).

The key insight: The minus side is always the sportsbook's implied favorite. The bigger the number (−300, −400), the heavier the favorite.

Point Spreads

A point spread levels the playing field. Instead of just picking who wins, you're picking who wins by how much.

Example: Chiefs −6.5 vs Eagles +6.5

If you bet the Chiefs −6.5, they need to win by 7 or more points for you to win. If you bet the Eagles +6.5, the Eagles need to either win outright OR lose by 6 or fewer points.

Point spread bets almost always pay around −110 (bet $110 to win $100). That extra $10 is the sportsbook's cut, called the "vig" or "juice."

Over/Under (Totals)

Instead of picking a winner, you're betting on the combined score of both teams.

Example: Chiefs vs Eagles, total 47.5

Over 47.5: You win if both teams score 48+ combined points

Under 47.5: You win if both teams score 47 or fewer combined

Totals also typically pay −110 on both sides.

Decimal Odds

Common in Europe, Canada, and Australia. Decimal odds include your stake in the return.

Example: 2.50 decimal odds means a $100 bet returns $250 total (your $100 stake + $150 profit).

To convert American to decimal:

Positive American (+130): divide by 100 and add 1 → 2.30

Negative American (−150): divide 100 by the number and add 1 → 1.67

Implied Probability

Every set of odds implies a probability of winning. This is the most useful concept in sports betting.

Positive odds: Implied probability = 100 ÷ (odds + 100)

+130 → 100 ÷ 230 = 43.5% implied probability

Negative odds: Implied probability = odds ÷ (odds + 100)

−150 → 150 ÷ 250 = 60% implied probability

Why this matters: If you think a team has a 50% chance of winning but the sportsbook gives them +130 (implying only 43.5%), you have an edge. Consistently finding these spots is how sharp bettors make money long-term.

The Vig Explained

Notice that if you add the implied probabilities for both sides of a bet, you get more than 100%. That's intentional.

Example: Chiefs −110 / Eagles −110

Chiefs implied: 52.4% + Eagles implied: 52.4% = 104.8%

That extra 4.8% is the sportsbook's margin — their guaranteed profit over time regardless of who wins. It's why most recreational bettors lose in the long run: they're fighting a built-in edge.

Quick Reference

Format	Example	$100 Bet Pays
American favorite	−150	$166.67
American underdog	+200	$300
Decimal	2.50	$250
Fractional	3/2	$250

Now that you know how odds work, you're ready to start comparing lines across sportsbooks — because the same game will have slightly different odds at DraftKings vs FanDuel vs BetMGM, and shopping for the best number is one of the simplest edges available to any bettor.