How Do Betting Odds Work?
Betting odds work as prices set by sportsbooks that combine an estimated probability with a built-in margin. A -110 line means you risk C$110 to win C$100 and implies a 52.4% chance. Both sides of a market always imply more than 100% combined, and the surplus, usually 4% to 6%, is the vig the book keeps regardless of the result.
How a Sportsbook Builds a Line
Odds start with a probability model. Oddsmakers, increasingly supported by third-party pricing feeds, estimate each outcome's chance, then shorten the prices to add margin. If a model says the Jets win 50% of games in a matchup, fair odds are +100 each way, but the book posts -110/-110. Each side now implies 52.38%, and the market totals 104.76%.
That surplus is the vig, and it means the book profits whenever action is reasonably balanced. On C$110,000 bet on each side of a -110 spread, the book collects C$220,000, pays out C$210,000 to winners, and keeps C$10,000 no matter which team covers. The bookmaker is selling a market, not gambling on games.
Different markets carry different margins. Main lines on NHL or NFL games run tight, around 4.5%. Player props, same-game parlays and obscure leagues can carry 8% to 15%, because there is less sharp money forcing the price to be accurate. As a rule, the further from the main markets you wander, the more you pay.
Why Odds Move Before the Game
Prices are opinions that get corrected by money. If sharp bettors hammer the Elks +6.5, books drop the line to +6, then +5.5, or shift the juice from -110 to -120 first. News moves lines too: a confirmed starting goalie or a scratched star forward can swing an NHL moneyline 20 cents in minutes.
The price at kickoff, called the closing line, is the market's most accurate estimate because it has absorbed all the information and money. Beating the closing line consistently, taking +140 on a team that closes +120, is the standard evidence that a bettor has real skill rather than luck. If your bets routinely close worse than you got, you are winning information battles the book has already lost.
What This Means for Your Bets
First, know your break-even. At -110 you need 52.38% winners just to tread water, and casual bettors picking sides at coin-flip accuracy lose the vig steadily. Second, compare implied probability to your honest estimate before betting, not after. If you cannot say why the book's 52.4% is wrong, the bet is entertainment, which is fine, as long as it is priced as such.
Third, exploit the one edge that requires no forecasting: line shopping. Ontario's open market licenses dozens of sportsbooks, and the same game routinely shows different prices across apps. Taking the best number every time can shave a point or more off the margin you pay, which for a regular bettor is worth hundreds of dollars a season.
Ready to put this to use? compare odds at licensed Canadian sportsbooks