How to read sports betting odds: American, decimal, and fractional formats

If you’re new to sports betting, the numbers next to a team or player’s name can feel like a foreign language. Odds are the backbone of every wager, they tell you the potential payout, the implied probability, and whether a bet is worth taking. The challenge? Odds aren’t displayed the same way everywhere.

In the United States, most sportsbooks use American odds with plus (+) and minus (–) signs. Elsewhere, you’ll often see decimal odds or fractional odds. While they look different, all three formats serve the same purpose: to show how much you could win and what the sportsbook thinks the chances are.

Also Read; What is a Sportsbook? Here’s a beginner’s guide to US online sports betting

This guide breaks down the three main odds formats—American, decimal, and fractional—in simple terms. By the end, you’ll know how to read them, convert between them, and use them to make smarter betting decisions.

American Odds Explained

American odds are the most common format in US sportsbooks. They are expressed with a plus (+) or minus (–) sign.

• Positive odds (+200): Show how much profit you’d make on a $100 bet.
  • Example: +200 means a $100 bet wins $200 (total return $300).
• Negative odds (–150): Show how much you need to bet to win $100.
  • Example: –150 means you must bet $150 to win $100 (total return $250).

Key takeaway: A minus sign indicates the favorite, while a plus sign shows the underdog.

Decimal Odds Explained

Decimal odds are the standard in Europe, Canada, and Australia, and are gaining popularity online. They’re simple: the number shows the total return (profit + stake) for every $1 bet.

• Example: 2.50 means a $1 bet returns $2.50 ($1 stake + $1.50 profit).
• Example: 1.80 means a $1 bet returns $1.80 ($1 stake + $0.80 profit).

Key takeaway: The higher the decimal, the bigger the potential payout and the lower the implied probability.

Also Read; Offshore sportsbooks vs legal US betting sites: Key differences explained

Fractional Odds Explained

Fractional odds are traditional in the UK and are still popular in horse racing. They’re written as a fraction, like 5/1 or 7/2.

• Example: 5/1 means you win $5 for every $1 staked. A $10 bet returns $60 ($50 profit + $10 stake).
• Example: 7/2 means you win $7 for every $2 staked. A $20 bet returns $90 ($70 profit + $20 stake).

Key takeaway: Fractional odds clearly show the profit relative to the stake, which is why many bettors still prefer them.

Converting Odds Between Formats

Being able to switch between odds formats helps when comparing sportsbooks or betting markets. Here’s a quick reference:

• American to Decimal: Positive odds → (odds/100) + 1. Negative odds → (100/odds) + 1.
• Decimal to Fractional: Subtract 1 from the decimal and convert to a fraction.
• Fractional to Decimal: Divide the fraction and add 1.

Example: –150 (American) → 1.67 (Decimal) → 2/3 (Fractional).

Why Odds Formats Matter for Bettors

• Comparison shopping: Some sportsbooks let you switch formats. Being fluent in all three helps you spot better value.
• Understanding probability: Odds reflect the bookmaker’s view of the chance of an outcome. Converting odds to implied probability helps identify mispriced bets.
• Global betting markets: If you’re reading international tips or betting on sports worldwide, you’ll encounter all formats.

FAQs

Q1: Which odds format should US bettors use?
Most US sportsbooks default to American odds, but many platforms allow you to switch to decimal or fractional if you prefer.

Q2: Are decimal odds easier to understand than American odds?
Yes, decimal odds are straightforward because they show the total payout per unit staked. American odds take practice but are useful once you get familiar.

Q3: Can odds formats change the actual payout?
No. The format only changes how the odds are displayed. The payout remains the same across formats once converted.

Q4: What is implied probability in betting odds?
Implied probability is the chance of an outcome based on the odds. For example, +200 odds imply a 33.3% chance, while –150 implies a 60% chance.

Q5: Why do UK bettors still prefer fractional odds?
Tradition plays a big role. Fractional odds have been used in horse racing for centuries and remain popular in British betting culture.