There are three main odds representations used by most bookmakers and sports betting websites.

Let’s run through some examples of decimal odds, fractional odds and American odds so that you understand how to calculate and convert odds – to understand how much you can win on various sports bets, and to calculate the implied probability % from sports odds on a specific outcome:

## American Odds

• Positive American Odds: These odds reflect how much you win on a single \$100 bet.  For example, a positive American odds @ +110 would win \$110 for a \$100 wager.
• Negative American Odds: The odds indicate how much you must bet in order to make \$100 profit. For example a wager on a team with American odds of -90 would win \$100 on a \$90 bet.

## Fractional Odds

This odds format is used primarily in the United Kingdom & Republic of Ireland. Fractional odds quote the potential profit which can be made on a bet if it wins, relative to the stake.

For example if \$500 is bet at odds of 2/1 the potential profit is \$1000 (\$500 * 2) and the total returned is \$1500 (\$1000 plus the \$500 stake).

## Decimal Odds

Decimal betting odds reflect the potential return if a bet succeeds, relative to the stake placed. For example if £\$ is bet at odds of 3.0 the total returned is \$15 (\$5 * 3)- and the potential profit is £10 (\$5 * 3 minus the initial \$5 stake).

## Implied Probability

Odds correlate to probability e.g a 2/1 bet is expected to win twice in every 3 attempts, hence the probability is 33.33%.

## Sports Betting Odds Calculator / Converter

Use our lookup table to convert odds and calculate the implied win probability of your sports bets.

## Implied Probability of Sports Bets

Calculating the implied probability is when you convert betting odds into a percentage (as outlined above in our odds calculator).

Working out the implied probability of a sports bet is straightforward – all you have to do is divide the risk by the return.

For example, wagering \$100 on a team to win with +150 American moneyline odds equates to a potential total return of \$250.

• Example of implied probability with +150 odds: \$100 Risk ÷ \$250 potential total return = 0.4 (40%).

Yet, as other factors affect a Vegas oddsmakers’ decisions when determining the odds on a specific outcome, the implied probability isn’t a correct reflection of your chances of winning.

For instance, a sportsbook may alter the betting odds to encourage sports bettors to wager on the opponent if they take too many bets on one side. Also, they include a vig (also known as the vig, vigorish, cut, or juice) to prevent them from paying out too much.

### What’s A Sportsbook Vig?

Bookmakers include a vig into betting odds to help them increase profit margins and avoid significant losses.

Let’s use an even odds (both teams are just as likely to win) NFL moneyline bet for the Los Angeles Chargers v Buffalo Bills at -110 as an example. Because it’s at even (pick’em) odds, a winning \$110 bet on either team will make you \$100.

Your sportsbook will give you your initial stake and winnings (110 original stake + \$100 winnings = total return of \$210) if your bet comes off, meaning you pay nothing.

But if someone else places a \$110 losing bet, the bookmaker will take \$110 from the other bettor. So, although the sportsbook pays you \$100 in winnings, it also takes \$110 from the losing bettor, resulting in a \$10 profit – this is a sports betting vig.

### Calculating the Implied Probability With Amercian Odds

To convert positive American odds to probability, use the formula of 100 ÷ (positive American odds + 100) x 100 = the implied probability percentage.

• Example of + 250 American odds: 100 ÷ (250 + 100) x 100 = 28.57%

For negative American odds, follow this formula: negative American odds ÷ (negative American odds + 100) x 100 = implied probability.

• Example of -120 American odds: 120 ÷ (120 + 100) x 100 = 54.54%

### Calculating the Implied Probability With Fractional Odds

The formula is different to work out the implied probability from fractional odds: denominator ÷ (denominator + numerator) x 100 = percentage of implied probability.

• Example with 8/2 fractional odds: 2 ÷ (8 + 2) X 100 = 20%

### Converting Decimal Odds into Implied Probability

To calculate the implied probability from decimal odds, use this formula: 1 ÷ (decimal odds x 100) = implied probability percentage.

• Example with decimal odds of 6.50: 1 ÷ 6.50 X 100 = 15.3%