How Betting Odds Work

Decimal, American and fractional: the three formats you'll see

Canadian sportsbooks usually let you switch odds display in the settings. The three formats describe the same thing differently.

• Decimal (2.10): the most common default on iGaming Ontario sites. Multiply your stake by the number for the total return. A $20 stake at 2.10 returns $42, of which $22 is profit.
• American (+150 / -130): a plus number shows profit on a $100 stake (+150 = $150 profit). A minus number shows how much you must stake to profit $100 (-130 = stake $130 to win $100). Common on US-facing books like DraftKings, FanDuel and BetMGM.
• Fractional (11/10): profit-to-stake. 11/10 means $11 profit for every $10 staked. Less common in Canada but still shown on some horse racing markets.

Quick conversions: decimal 2.10 = +110 American = 11/10 fractional. If a format confuses you, switch the display — the underlying price never changes.

Turning odds into implied probability

This is the single most useful skill for a bettor. Implied probability tells you what chance the odds are assigning to an outcome, so you can judge whether you think the real chance is higher (value) or lower (avoid).

For decimal odds the formula is simple:

Implied probability = 1 ÷ decimal odds

• 2.00 → 1 ÷ 2.00 = 0.50 = 50%
• 1.50 → 1 ÷ 1.50 = 0.667 = 66.7%
• 4.00 → 1 ÷ 4.00 = 0.25 = 25%

For American odds: - Negative (-130): 130 ÷ (130 + 100) = 0.565 = 56.5% - Positive (+150): 100 ÷ (150 + 100) = 0.40 = 40%

If you think a team's real chance of winning is 60% and the price implies only 50% (2.00), you have found positive expected value. That judgement is yours to make — the number just tells you what the market is pricing.

The margin: why the probabilities add up to more than 100%

Add up the implied probabilities on a two-way market and you'll get more than 100%. That extra slice is the bookmaker's margin (also called the overround or vig), and it's how the operator makes money regardless of the result.

Example from a UFC fight priced two ways: - Fighter A at 1.80 → implied 55.6% - Fighter B at 2.10 → implied 47.6% - Total = 103.2%

The 3.2% over 100% is the margin. A fair, margin-free market would price the same two fighters at higher odds. The lower the margin, the more the price returns to you over time.

Across a sampled set of markets, BETAURO's odds data shows real differences in average margin between Ontario operators:

• Pinnacle: average margin ~3.1% (sample 221)
• FanDuel: ~4.1% (sample 306)
• DraftKings: ~4.2% (sample 898)
• BetMGM: ~4.7% (sample 240)
• Caesars Sportsbook: ~5.3% (sample 784)
• Unibet: ~5.7% (sample 201)
• Betway: ~6.1% (sample 191)
• BetRivers: ~6.3% (sample 280)
• 888sport: ~6.6% (sample 251)
• LeoVegas: ~6.9% (sample 167)

Lower margin means better prices on average — that's the factual basis for Pinnacle's odds rating of 9.4 and the reason sharp bettors watch margin closely.

A full worked example: NHL moneyline

Say the Toronto Maple Leafs are playing the Montréal Canadiens and you want to back Toronto on the moneyline (to win the game, including overtime/shootout depending on market rules).

Suppose two Ontario books price Toronto like this: - Book A: 1.71 → implied 58.5% - Book B: 1.80 → implied 55.6%

Both describe the same bet, but Book B's price is better because it implies a lower probability — meaning you're paid more for the same outcome. Now run the money on a $50 stake:

• At 1.71: return = 50 × 1.71 = $85.50, profit $35.50
• At 1.80: return = 50 × 1.80 = $90.00, profit $40.00

That's a $4.50 difference on one bet from a price gap of just 0.09. Multiply that across a season of hockey bets and line shopping — checking who has the best price before you stake — becomes the most reliable edge available to a recreational bettor. This is why BETAURO's data tracks 'best price share': the proportion of sampled markets where each operator posted the top price. In that sample, DraftKings led with about 54% and Pinnacle about 53%, while several others sat in single digits.

Odds ratings vs. best price share: reading BETAURO's data

Two different data points describe pricing, and they don't always move together.

• Average margin measures how much the book bakes in across a market — lower is better for you.
• Best price share measures how often that book happened to post the single highest price in a sampled matchup.

Pinnacle scores highest on odds (9.4) thanks to a low ~3.1% margin, but it's a stripped-back product: its features list is Live Betting and Fast Payout only, and it rates 6.0 on Bet Builder and 7.6 on app. bet365 sits at 8.8 for odds but far higher on breadth — 9.6 market coverage, 9.3 app, and features including Live Streaming, Cash Out and Bet Builder.

So the trade-off is plain: - Choose a low-margin book like Pinnacle if raw price is your priority and you don't need same game parlays or streaming. - Choose bet365, DraftKings or FanDuel if you want strong prices plus a deep app, live streaming and Same Game Parlay / Bet Builder tools.

No single operator wins on everything. Line shopping across two or three of them captures the best price on each individual bet.

How odds move before and during a game

Odds are not fixed. They shift as money comes in and as new information appears — an injury, a confirmed starting goalie, weather at an NFL game, or a fighter missing weight in the UFC. When a lot of money backs one side, the book shortens that price (lowers the odds) to balance its book and protect its margin.

This matters for two reasons. First, an early price can be better or worse than the closing price, so timing your bet affects value. Second, live (in-play) odds change second by second as the game unfolds — most Ontario books offer Live Betting, and many add Cash Out so you can settle a bet early at the current value rather than waiting for the final whistle. Cash Out prices carry their own margin, so the amount offered is usually a little below the bet's raw current worth.

Legal and practical context in Canada

Online sports betting in Canada is regulated province by province, not federally. In Ontario, the AGCO and iGaming Ontario license and oversee operators — every book covered here (bet365, DraftKings, FanDuel, BetMGM, Caesars Sportsbook, Betano, Betway, Unibet and the rest) is listed as licensed under iGaming Ontario. That is not a Canada-wide licence: other provinces run their own regimes through provincial lottery corporations and regulators, so which operators are legally available depends on where you live. The minimum age for regulated betting is 19.

On the practical side, the operators in this guide share a $10 minimum deposit, withdrawal windows quoted at 0–24h, and Interac support, with Visa widely accepted and Apple Pay available at bet365, Betway, Unibet, theScore Bet and LeoVegas. None of that changes how odds work — but a licensed, well-regulated book is where the odds you read are the odds you're paid.