- Decimal = total return per C$1, stake included
- American: +150 means C$150 profit on C$100; -200 means you stake C$200 to win C$100
- Implied probability = 1 / decimal odds
- Margin = 1 - 1 / (sum of implied probabilities of every outcome)
The three formats, side by side
| Decimal | American | Fractional | Implied chance |
|---|---|---|---|
| 1.50 | -200 | 1/2 | 66.7% |
| 1.91 | -110 | 10/11 | 52.4% |
| 2.00 | +100 | 1/1 (evens) | 50.0% |
| 2.50 | +150 | 3/2 | 40.0% |
| 4.00 | +300 | 3/1 | 25.0% |
| 11.00 | +1000 | 10/1 | 9.1% |
All figures are computed from the formulas on this page. The odds are the same price written three ways: a C$100 bet at 2.50, +150 or 3/2 returns C$250 in total if it wins.
Why the margin matters most
A fair coin flip priced by a sportsbook rarely shows 2.00 on both sides. At 1.91 and 1.91 the implied chances add up to 104.7%, and that extra 4.7 points is how the book gets paid whichever side wins. Over many bets, a lower margin returns more of your stakes. Comparing the margin on the same market across sportsbooks is one of the few edges a bettor fully controls. Our guide to bookmaker margin goes deeper, and how to read betting odds covers every format step by step.
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FAQ
How do I convert American odds to decimal?
For positive American odds, divide by 100 and add 1: +150 becomes 2.50. For negative odds, divide 100 by the number without its minus sign and add 1: -200 becomes 1.50. Decimal odds always include your stake.
What is implied probability?
It is the chance of winning that the odds price in: 1 divided by the decimal odds. Odds of 2.00 imply 50%, odds of 1.50 imply 66.7%. Because sportsbooks build a margin into their prices, the implied chances of every outcome in a market add up to more than 100%.
How do I work out a sportsbook margin?
Add up the implied probabilities of every outcome in the market. Two outcomes at 1.91 each add up to 104.7%. The margin is 1 minus 1 divided by that total, here about 4.5%. The margin box below does it for up to three outcomes.
Which odds format do Canadian sportsbooks use?
Most sportsbooks serving Canada let you switch between decimal and American odds in the settings, and many also offer fractional. The format never changes the payout, only how the price is written.
Why does the fractional odds result look rounded?
Fractional odds are written as whole-number ratios, so the converter finds the nearest fraction with a denominator up to 100. Decimal and American odds are exact; use them when the last cent matters.