How do odds / prices work?

The sports odds, or price, on a given event can be rendered by an online sportsbook in one of three ways.

Decimal Odds

When using decimal odds, the underdog has the higher of the two numbers, while the favourite has the lower of the two (or three). In order to figure out how much money your winning bet will earn you, you must multiply your wager by the decimal number shown and that total is how much you’ll win.

In our example above, Leicester City, priced at 3.28, are playing Liverpool FC, priced at 1.97. Leicester City, with the higher number, is the underdog. A $10 bet on Leicester City would result in a $32.82 payout (including your original wager) if they were to win the match. The same $10 bet on the favourite – Liverpool FC – would result in a win of $19.71 (including your original bet). If you wagered that the match would result in a draw, and it did, your $10 bet would earn you a payout of $35.03, including your initial $10 wager.

To calculate decimal from American odds, you divide the moneyline odd by 100, and then add 1. For calculating negative American odds to the decimal odds, you’d divide 100 by the negative moneyline odd, and then add 1.

American Odds

If you’re looking at number like -120, +240, or another three-digit number with a plus or minus (+/-) in front of it, those are called American odds. 

In the example above, the Edmonton Oilers and the Ottawa Senators game has the Oilers priced as -215 favourites. The Senators are +180 underdogs. 

If you want Edmonton -215 to win, you'll have to risk $2.15 for every $1 you want to win. 
If you want Ottawa +180 to win, for every $1 risked, you win $2.80 (includes stake)

Fractional Odds

Fractional odds are not as commonly used in North America, with one exception: horse racing.  The calculation for working out how much money you can win – compared to your bet – is shown like this: 9/1. The number on the left (9) is how much you will win. The number on the right is how much you need to bet.

In our example above, you can see a futures bet on a horse winning the Triple Crown in 2021. If you have a good feeling about Essential Quality, who at this time had 40/1 odds to win it all, your $1 bet would earn you $41, including your original wager. Let’s say you put $25 on Essential Quality and he won the Triple Crown. Your payout would be $1,025, including your original bet.


At Sports Interaction, you can select whichever style of odds you’re most comfortable with in your account settings or on the footer of the site.

For more information on betting, check out our betting guide

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