How to Read Betting Odds

Odds tell you two things: how much a bet pays and how likely the sportsbook thinks it is. Once you can read a line like Leafs -130 or Over 6.5 (+105), the rest is easy. Here is the whole thing in plain English, with the math done for you. (The teams and prices below are examples, not picks.)

American odds: minus and plus

North American sportsbooks show American odds, built around $100.

• Minus (-) marks the favourite. The number is what you risk to win $100. At -150 you risk $150 to win $100.
• Plus (+) marks the underdog. The number is what a $100 bet wins. At +150 a $100 bet wins $150.
• +100 (also written EVEN) means you win what you risk.

You don't have to bet $100. The math scales: a $20 bet at +150 wins $30, and a $20 bet at -150 wins $13.33.

Decimal odds are the total return for each $1, stake included. Many Canadian sportsbooks let you switch to them.

Moneyline: just pick the winner

A moneyline bet only asks who wins. Example: Maple Leafs -130, Canadiens +110. A $100 bet on the Leafs wins $76.92; a $100 bet on the Habs wins $110. In hockey the moneyline includes overtime and the shootout. Some books also offer a three-way moneyline for regulation time only, where a tie is its own outcome.

Point spreads, puck lines and run lines

A spread evens out a mismatch by giving the underdog a head start. Example: Bills -3.5 (-110), Dolphins +3.5 (-110).

• Bills -3.5 wins if the Bills win by 4 or more.
• Dolphins +3.5 wins if the Dolphins win, or lose by 3 or fewer.
• With a whole number like -3, a 3-point Bills win is a push: the bet is refunded. The half point (the hook) is there to stop that.

Hockey and baseball use a fixed spread of 1.5, called the puck line and the run line. Since 1.5 is a small number, the price does the adjusting: a favourite at -1.5 often pays plus money, because it has to win by two.

In the NFL, 3 and 7 are key numbers because so many games are decided by a field goal or a touchdown. Getting +3.5 instead of +2.5 is worth a lot more than the half point looks.

Totals (over/under)

A total is a bet on the combined score. Example: Over/Under 47.5 (-110). A 27-21 final is 48 points, so the over wins. Hockey totals are usually 5.5 to 6.5 goals and baseball totals 7 to 9.5 runs. At most sportsbooks overtime and extra innings count.

Implied probability: what the odds really say

Every price hides a win chance. The formulas:

• Minus odds: odds / (odds + 100), using the number without the minus. -150 is 150 / 250 = 60.0%.
• Plus odds: 100 / (odds + 100). +150 is 100 / 250 = 40.0%.

A bet is only worth it if you think the real chance is higher than the implied one. That is the whole game. The Locksmith's model starts from exactly this: it compares the chance built into the market price with ESPN's win probability before he picks.

The juice (vig): how the house gets paid

Price both sides of a game at -110 and add up the implied chances: 52.4% + 52.4% = 104.8%. The extra 4.8% over 100% is the sportsbook's cut, the juice. Over time it keeps about 4.5% of the money bet on a game like that.

It also means you need to win 52.4% of your bets at -110 just to break even. Hitting 55% over a full season is excellent; anyone claiming 80% is selling something.

Parlays: bigger payouts, harder to hit

A parlay ties several bets together. Every leg has to win, and the odds multiply. Turn each leg into decimal odds and multiply:

• 2 legs at -110: 1.909 x 1.909 = 3.64. A $100 parlay returns $364.46, a profit of $264.46 (about +264).
• 3 legs at -110: 6.96, a $595.79 profit on $100 (about +596).

The catch: three coin flips at -110 all land only about 12.5% of the time. At most sportsbooks a leg that pushes is dropped and the parlay pays at the odds of the legs that are left.

Units and bankroll

Serious bettors keep score in units, not dollars, so records compare fairly. One unit is usually 1% to 2% of a bankroll. On SportsMafia, 1 unit is $100 of a $10,000 virtual bankroll. The Locksmith sizes plays at 1, 2 or 3 units, so a 3-unit win at +140 is +4.20 units and a 3-unit loss is -3 units. See every graded ticket on The Locksmith's picks record.

Sports betting in Canada: the basics (19+)

• Betting on a single game has been legal in Canada since August 27, 2021, when the Safe and Regulated Sports Betting Act (Bill C-218) changed the Criminal Code. Before that, only parlays were allowed.
• Each province decides who can offer betting. Ontario opened its regulated market to licensed private sportsbooks on April 4, 2022, overseen by the AGCO and iGaming Ontario. You have to be 19 or older and physically in Ontario to bet.
• In most other provinces, legal online betting runs through the provincial lottery corporation, for example PlayNow in British Columbia, PlayAlberta, and Mise-o-jeu in Quebec. OLG's PROLINE also operates in Ontario.
• The minimum age is 19 in most provinces and 18 in Alberta, Manitoba and Quebec.
• Before you sign up anywhere, check that the sportsbook is licensed in your province.
• SportsMafia is not a sportsbook. We take no bets. Our picks are free, our contests use virtual money, and the site is for members 19 and older.

General information, not legal advice. Rules can change, so check your provincial regulator for the latest.

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Picks are for entertainment and discussion. SportsMafia is not a sportsbook and takes no bets; our contests use virtual money only. 19+. If betting stops being fun, help is free and confidential: ConnexOntario 1-866-531-2600, or see Responsible Gaming. Page data updated 3:44 PM ET.