Free Betting Odds Calculator & Converter

How to use the betting odds calculator?

Using this sports betting odds calculator is simple. You'll need to fill out two fields above – one for your bet amount and one for the betting odds. You can enter the odds in three formats: American, fractional, or decimal. Once both fields are filled, the calculator will display the implied probability of the wager and how much you stand to win if the bet is a winning wager.

How are sports betting odds calculated?

Sports betting odds are calculated with the main goal for sportsbooks being to receive equal money on both sides of a bet.

For example, if the Kansas City Chiefs are a -10 point favorite against the Oakland Raiders and are getting 90% of the money, the sportsbook would likely adjust their line so they don't finish in the negative if the Chiefs cover that spread. 

And so, the sportsbook will continue to raise the line until the other side starts receiving action (from 10.5 to 11 to 11.5, etc). While receiving equal money isn't always possible, it's always the goal because if that's the case, the sportsbook will come out in the positive no matter the final result.

That's because of the vig, or the amount the sportsbook charges for taking a bet. In the above situation, if equal money was put on the Chiefs -10 (-110) and Raiders +10 (-110), the sportsbook would finish in the positive no matter the result. Say there is one bet on each side, $110 to win $100. 

If the Chiefs win by seven points and don't cover, the Chiefs bettor is out $110, while the Raiders bettor is up $100. That extra $10 goes to the sportsbook because of the -110 odds and that's why the sportsbook wants equal money.

To best understand how odds are calculated, it's best to learn what they specify. Sports betting odds and lines specify the implied probability of an outcome and how much money can be won. 

How do sports betting odds work?

Sports betting odds and lines specify the implied probability of an outcome and how much money can be won.

Odds can refer to moneyline, spread, and total bets, and they can be displayed as American, British (fractional), or European (decimal). While the odds look different, they mean the same thing. 

American Odds

Most sports betting apps in the United States use American Odds. The main signifiers of American odds are that they either have a plus (+) or minus (-) in front of them and are in terms of 100.

Understanding plus (+) and minus (-) odds is the most important thing before learning about American odds.

Plus and Minus Odds

The plus (+) and minus (-) in sports betting can refer to either the point spread or betting odds. In terms of the spread, the " - " always refers to the favorite and the " + " always refers to the underdog.

For example, you can bet the Dallas Cowboys as a -7 point favorite to beat the Green Bay Packers or the Packers as a +7 point underdog. If you bet the Cowboys -7 and they win by more than seven points, you win your bet. Similarly, if you bet the Packers +7 and they lose by less than seven points or win outright, you win your bet.

Decimal Odds

Decimal odds are most popular in Australia, Canada, Europe and New Zealand. These odds may be the easiest of the three to understand just by looking at the numbers.

The team with the higher of the two numbers is the underdog and the team with the lower of the numbers is the favorite. The return can be calculated by multiplying the bet with decimal odds.

Fractional Odds

Fractional odds are most popular in the United Kingdom and Ireland, and are often the choice for horse racing. Also, a lot of sports betting sites in the United States will use fractional odds for futures odds.

Example odds to win the Super Bowl:

Similar to decimal odds, the return can be determined by multiplying the odds and the bet. Above, 100 times 2.5 (5/2) equals 250. In horse racing, odds will dip to something like 3/5 or 5/7 which usually means that horse is a big favorite. A 3/5 favorite is equal to -167 in American odds and 1.6 in decimal odds.

Implied Odds vs. True Odds

Implied odds are the conversion of a sportsbook's offered odds into an implied probability of an outcome. For example, a standard football spread bet often comes with odds of -110 for both sides, translating to an implied win probability of 52.38%. This means the sportsbook believes each outcome has a 52.38% chance of happening.

True odds, on the other hand, reflect the bettor's personal estimation of the likelihood of an outcome. Using the same example, if a bettor believes that the true probability of the outcome is 52.38% or higher, the bet offers good value. 

While sportsbooks set implied odds based on market factors, true odds are subjective and calculated through methods like predictive models or handicapping. If your calculated true odds exceed the implied odds, it's considered a value bet.

What is a Moneyline Bet in Betting?

A moneyline bet is on the straight-up winner of a game.

Moneyline bets are as straightforward as it gets in sports betting. You're betting on which side will win an event and if that side wins, you win.

What is Spread Betting & How Does it Work?

A spread bet is on the forecasted point differential between two teams. A minus (-) indicates the favorite and a plus (+) is the underdog. You can use the best sportsbook promos to make spread bets on the top sportsbooks in the US today. 

In each bet, a push is also possible if the Lakers win by exactly seven points. That would mean each side gets their money back.

As for the odds, the most common number for spread bets is -110, but that number varies depending on the location, sportsbook, and how popular each side is. The typical number is -110, which means you have to bet $110 to win $100. However, there are states where odds are worse in order to get the state more money such as -115 or -120. This is also called the vig, which is the amount the sportsbook charges per bet.

If two teams are equal, PK will be given alongside a team name which means the matchup is considered a "pick 'em." In this case, point spread doesn't matter as this boils down to a moneyline bet and a tie would get your money back.

What Does Over Under Mean in Betting?

An over/under bet applies to the score or points in a given contest.

The below over/under table is for the Dallas Cowboys and New York Giants game.

Similar to a spread bet, if the Cowboys and Giants combine for exactly 49 points, it's a push and each side gets their money back. Also similar to spread bets is that the odds can vary.

Do you have more questions about betting? Check out our sports betting Q&As now.