Payouts and profits may vary slightly depending on methodology and rounding when converting odds or calculating parlays. All payout and profit numbers here are shown for illustrative purposes only and may vary slightly from actual payouts and profits.

Odds define the likelihood of an outcome for each side of a competition. When talking about sports betting odds, they're often explained with a simple "number to number" explanation, with the unfavorable outcome preceding the favorable one. For instance, if the odds of winning a contest are 3 to 1, the chances of losing are effectively three times greater than the odds of winning.

American Odds

While not as simple to read as decimal or fractional odds at first, American gambling odds become fairly easy to understand once you know how to read them. American odds center bets around $100, with the favored outcome listed differently than the underdog. Though this system bases odds around $100, larger or smaller bets scale easily in this system. For example, a bet that would pay $200 on a $100 bet pays $20 on a $10 bet.

When each participant shows a plus or minus sign preceding the odds, such as +150 or -150, this indicates the more favored player or team versus the less favored, with the minus sign indicating the favorable bet (the bet with the higher probability of success - the favorite) and the plus sign depicting the unfavorable one (the bet with the lower probability of success - the underdog).

How to calculate winnings with American odds (Negative vs Positive odds)

When expressing odds with a minus sign, this shows the amount you have to wager in order to win back $100. For example, odds of -120 mean that placing a bet of $120 wins $100. In every case you win, the bookmaker also returns your initial stake. So, you'd walk away with $220 total in the event you were to win this example wager.

The plus sign preceding the odds expresses how much you'll win with a $100 stake. For instance, odds that read +120 indicate you'll win $120 if you stake $100. As with negative odds, you also win back your initial stake—which means you ultimately walk away with a total of $220 if you win this bet.

Though American bets are based on $100 increments, you aren't always expected to bet $100 on positive odds or bet to win $100 on negative odds. American odds scale easily. For example, in a +120 bet, you can wager $10 to win back $12—for a total of $22. In a -120 bet, you can stake $12 to win back $10 and walk away with your initial wager plus your winnings—a total of $22.

How to calculate implied probability with American odds (Negative vs Positive odds)

Implied probability describes the percent chance that a selection has of winning their matchup.

The graphic below shows the odds on a fictional game between Chicago and Denver.

The simplest way to determine the implied probability with American odds is by dividing 100 by the odds plus 100. The table below shows how to calculate the likelihood the bet sheet gives Chicago to win at +120 odds.

Implied probability with negative odds is calculated somewhat differently. Divide the odds by the odds minus 100, as indicated in the table below, giving the chance in percentage points of Denver winning the matchup.

Decimal Odds

For newer bettors, decimal odds might just be the easiest of odds types to read. They’re usually depicted by a whole number, followed by a two-place decimal. For example, a betting sheet might show 2.20 betting odds.

How to calculate winnings with decimal odds

To determine your potential winnings with decimals, all you need to do is multiply your stake by the indicated odds number. For instance, by making a $100 wager with 2.20 as the indicated betting odds, you'd multiply $100 by 2.20. This will return $220 if you win, which includes your $100 stake.

How to calculate Implied Probability with decimal odds

Calculating implied probability with decimal odds is just as simple as it is to determine potential returns. Simply divide 1 by the odds to find the percent chance that oddsmakers give your player or team to win. In the example of 2.20 decimal odds, you calculate 1 ÷ 2.20, which comes to a 45% chance of winning.

Fractional Odds

Fractional odds are much more common outside the United States, but some American bookmakers and apps use fractional odds as well. There's no trick to understanding how to read fractional sports betting odds. They're fairly straightforward and usually represented with a dash, as in 2-1 odds, with a colon, as in 2:1 odds, or with a slash, as in 2/1 odds.

How to calculate winnings with fractional odds

Fractional odds are among the easiest to calculate. To determine your profit, multiply your betting amount by the fraction. For example, a $100 bet on 6/5 odds pays $100 x (6/5), which comes out to $120 if you win, plus your initial $100 stake, meaning that your payout comes out to $220.

How to calculate implied probability with fractional odds

Implied probability is as straightforward as fractional odds. It's as simple as dividing the denominator by the sum of the denominator and the numerator (Denominator / (Denominator + Numerator)). For example, with 3/1 odds you would simply divide 3 by 4, giving you a 25% probability of your wager to win.

Odds indicate the likelihood of an outcome and help determine payouts. When betting, it’s important to understand the difference between implied odds and true odds.

Implied Odds

Implied odds represent the implied win probability based on the current sportsbook odds offered. You can easily calculate the implied probability for any wager by using our betting odds calculator above.

True odds

True odds are the actual odds of an outcome happening, which is subjective. There is no way to be certain of an outcome, but predictive models and data help bettors determine the likelihood of an outcome. If the true probability determined is higher than a Sportsbook’s implied probability, then a bettor might take that bet.

For example, let's say a basketball game is about to take place between Team A and Team B. After analyzing the teams' performance, statistics, and various factors, a bettor calculates the true probability of Team A winning to be 60% (represented as -150 in American odds). However, the sportsbook's implied probability, based on their odds, suggests that Team A has a 45% (represented as +122 in American odds) chance of winning.

In this scenario, the bettor recognizes a positive expected value opportunity. Since the bettor's true probability (60%) is higher than the sportsbook's implied probability (45%), there is a perceived edge in favor of Team A. The bettor might decide to take that bet because they believe the sportsbook has underestimated Team A's chances of winning. By placing a bet on Team A, the bettor expects to gain an advantage in the long run, given that their true probability assessment is more accurate than the sportsbook's estimation.

Now that you know the ins and outs of reading odds, check out our odds calculator for more details on conveniently calculating payouts.