How to read betting odds
Betting · Canada 
Odds do two jobs at once. They tell you what a bet pays, and they tell you how likely the sportsbook thinks the result is. Read them both ways and you see the price for what it is, including the slice the book keeps. This guide covers the three formats Canadian bettors meet, how to convert between them, and how to pull the bookmaker's margin out of any line. Every number below is worked out step by step, so you can check it yourself or run it through our odds converter.
The three formats at a glance
The same price can be written three ways. A coin-flip-style market at fair odds is 2.00 in decimal, +100 in American and 1/1 ("evens") in fractional. They pay exactly the same.
| Format | How it reads | Example | What a 100 stake returns |
|---|---|---|---|
| Decimal | Total return per 1 staked, stake included | 2.50 | 250 (150 profit) |
| American, plus | Profit on a 100 stake | +150 | 250 (150 profit) |
| American, minus | Stake needed to win 100 profit | -150 | 166.67 (66.67 profit) |
| Fractional | Profit per unit staked | 3/2 | 250 (150 profit) |
Provincial products lean decimal: Loto-Quebec's Mise-o-jeu prints decimal odds and multiplies them for multi-selection bets, and BCLC's PlayNow Sports carries its own odds primer. Offshore books licensed outside Canada usually let you switch format in the account settings. Pick the one you can do maths in quickly. For most people that is decimal.
Decimal odds: the easiest maths
Decimal odds are the total you get back for each dollar staked, including the dollar itself.
- Return = stake x decimal odds
- Profit = stake x (decimal odds - 1)
A C$20 bet at 2.50 returns C$50, which is C$30 profit. At 1.40 the same C$20 returns C$28, or C$8 profit. Anything under 2.00 is a favourite: you risk more than you win. Anything over 2.00 is an underdog.
Decimal odds also make parlays simple, because you multiply the legs together. Our parlays guide and the parlay calculator do that for you.
American odds: plus and minus
American odds are built around a 100 unit.
- Minus (favourite): the number is what you stake to win 100. At -140 you stake 140 to win 100.
- Plus (underdog): the number is what you win on a 100 stake. At +120 you win 120.
So -140 and +120 are a typical pair for a favourite and an underdog. Your stake does not have to be 100; scale it.
Worked example: Toronto -140, Montreal +120 (illustrative NHL moneyline). C$20 on Toronto wins 20 x 100 / 140 = C$14.29 profit, C$34.29 back. C$20 on Montreal wins 20 x 120 / 100 = C$24 profit, C$44 back. In decimal the same prices are 1 + 100/140 = 1.714 and 1 + 120/100 = 2.20, and 20 x 1.714 = 34.29, 20 x 2.20 = 44. Same money, two notations.
A line written as "-110 / -110" is the standard price on point spreads, puck lines and totals. You stake 110 to win 100, decimal 1.909. That small shortfall from 2.00 on both sides is the book's margin, covered below.
Fractional odds
Fractional odds are profit over stake. 5/2 means 5 profit for every 2 staked; 4/6 means 4 profit for every 6 staked. They are common for horse racing, golf outrights and UK-facing books, less so in Canada.
- Decimal = 1 + (numerator / denominator)
- 5/2 = 1 + 2.5 = 3.50
- 4/6 = 1 + 0.667 = 1.667
When the top number is bigger than the bottom, it is an underdog price. When it is smaller ("odds-on"), it is a favourite.
Conversion formulas
Keep these five lines and you can convert anything.
| From | To | Formula | Example |
|---|---|---|---|
| American plus | Decimal | 1 + A / 100 | +175 = 2.75 |
| American minus | Decimal | 1 + 100 / abs(A) | -125 = 1.80 |
| Decimal 2.00 or more | American | +(D - 1) x 100 | 4.50 = +350 |
| Decimal under 2.00 | American | -100 / (D - 1) | 1.40 = -250 |
| Fractional a/b | Decimal | 1 + a / b | 3/1 = 4.00 |
Checks on the examples: 1 + 175/100 = 2.75. 1 + 100/125 = 1.80. (4.50 - 1) x 100 = 350. 100 / (1.40 - 1) = 250, so -250. 1 + 3/1 = 4.00.
Implied probability: what odds say
Every price hides a probability. For decimal odds it is 1 divided by the odds.
- 2.00 = 50%
- 2.50 = 40%
- 1.40 = 71.4%
For American odds you can go direct:
- Minus price: abs(A) / (abs(A) + 100). -140 = 140 / 240 = 58.33%.
- Plus price: 100 / (A + 100). +120 = 100 / 220 = 45.45%.
The table below covers the prices you will see most. Every row is computed from the formulas above.
| Decimal | American | Fractional | Implied probability |
|---|---|---|---|
| 1.25 | -400 | 1/4 | 80.0% |
| 1.50 | -200 | 1/2 | 66.7% |
| 1.67 | -150 | 4/6 | 60.0% |
| 1.91 | -110 | 10/11 | 52.4% |
| 2.00 | +100 | 1/1 | 50.0% |
| 2.50 | +150 | 3/2 | 40.0% |
| 3.00 | +200 | 2/1 | 33.3% |
| 4.00 | +300 | 3/1 | 25.0% |
| 6.00 | +500 | 5/1 | 16.7% |
| 11.00 | +1000 | 10/1 | 9.1% |
| 1.25 | 80% |
|---|---|
| 1.50 | 66.7% |
| 1.67 | 60% |
| 1.91 | 52.4% |
| 2.00 | 50% |
| 2.50 | 40% |
| 3.00 | 33.3% |
| 4.00 | 25% |
| 6.00 | 16.7% |
| 11.00 | 9.1% |
The curve flattens fast. Going from 1.25 to 2.00 drops the implied chance by 30 points; going from 6.00 to 11.00 drops it by fewer than 8. Long prices look generous, but each extra point of odds buys less and less probability.
Finding the margin in any line
Add up the implied probabilities of every outcome in a market. If the book priced it fairly, the total would be exactly 100%. It never is. The amount above 100% is the overround, and it is how the book gets paid.
Take the Toronto -140 / Montreal +120 line again:
- Toronto: 58.33%
- Montreal: 45.45%
- Total: 103.79%
The margin, meaning the share of all stakes the book expects to keep if money comes in evenly, is 1 - 1/1.0379 = 3.65%. You can also strip the margin out to see the book's "fair" view:
- Toronto: 58.33 / 103.79 = 56.20%, fair decimal 1.779 (about -128)
- Montreal: 45.45 / 103.79 = 43.80%, fair decimal 2.283 (about +128)
So the real gap between the two sides is narrower than -140 / +120 suggests. Our bookmaker margin guide goes deeper, including three-way soccer markets and futures, where margins run higher.
The quick benchmark: a two-way line at -110 / -110 has implied probabilities of 52.38% each, an overround of 104.76% and a margin of 4.55%. A line at -105 / -105 cuts that to about 2.4%. Shopping the same bet at two books is the simplest way to pay less of it, which is one of the points in our guide to choosing a sportsbook.
Break-even win rate
Implied probability doubles as the hit rate you need just to break even over time.
| Price you take | Break-even win rate |
|---|---|
| -200 (1.50) | 66.7% |
| -110 (1.91) | 52.4% |
| +100 (2.00) | 50.0% |
| +150 (2.50) | 40.0% |
| +300 (4.00) | 25.0% |
At -110 you need to win 52.4% of your bets to stay level. Pick winners at exactly 50% and you lose 4.55% of turnover over time. That is the number to keep in mind when someone online claims a 55% record: it is possible over a short run, and very hard to hold.
Odds and expected value
Implied probability also lets you put a number on a bet, if you have your own estimate of the chance. Expected value per bet is the win times your probability minus the stake times the chance of losing.
Say Calgary is +130 (2.30), implying 43.48%, and your own view is 45%. Per 100 staked: 0.45 x 130 - 0.55 x 100 = 58.50 - 55.00 = +3.50. If your view is 40%: 0.40 x 130 - 0.60 x 100 = 52 - 60 = -8.00.
Two cautions. First, your estimate has to be better than the book's, and the book has more data than almost anyone. Second, a positive expected value is a long-run average, not a prediction: a bet you price at 45% still loses 55% of the time. Treat this as a way to see what a price assumes, not as a system.
What odds do not tell you
Odds are the book's price, not a prediction you have to accept, and not a promise.
- They include margin. As shown above, the raw implied probabilities overstate every outcome a little.
- They move. Injuries, line-ups, weather and the flow of money shift prices. Loto-Quebec states on Mise-o-jeu that it may modify odds at its discretion, and offshore books reserve the same right in their terms. The odds that count are the ones on your confirmed bet slip.
- They do not cover settlement rules. A hockey moneyline may or may not include overtime and the shootout; a regulation-time market is three-way. Read the market label. Our moneyline, spread and totals guide and the NHL betting guide show where this bites.
Reading a full bet slip
Here is how one game shows up in all three formats on a typical slip. Edmonton vs Calgary, illustrative prices:
| Market | Edmonton | Calgary |
|---|---|---|
| Moneyline (American) | -150 | +130 |
| Moneyline (decimal) | 1.667 | 2.30 |
| Puck line (American) | -1.5 +160 | +1.5 -190 |
| Puck line (decimal) | 2.60 | 1.526 |
| Total 6.5 goals | Over -110 / Under -110 |
The moneyline pair works out to 60.00% + 43.48% = 103.48%, a margin of 3.36%. The puck line flips the picture: Edmonton has to win by two or more, so its price lengthens to +160 (2.60), while Calgary at +1.5 becomes the favourite at -190 (1.526). Where the line sits matters as much as who you pick.
Common reading mistakes
- Treating minus as "lose". -150 is a favourite, not a negative return. You still profit if it wins; you just risk more to get less.
- Comparing decimal and American at a glance. 1.80 and +180 look close and are not: 1.80 is -125, while +180 is 2.80.
- Forgetting the stake in decimal returns. 2.50 on C$10 is C$25 back, but only C$15 is profit.
- Ignoring rounding. Books round displayed odds. -110 is 1.909, often shown as 1.91. Over a parlay the rounding compounds, so trust the slip total, not your head.
Odds and bonus terms
Sportsbook promotions are written in odds. A welcome bonus may require bets at minimum odds of 1.50 or 1.60; a parlay boost may require three legs at 1.20 or more each. Converted, 1.50 is -200 and 1.60 is -167, so the book is ruling out heavy favourites. Our betting bonus terms guide turns those conditions into money, and the free bets guide shows why the odds you pick change what a free bet is worth. Current offers sit on the betting bonuses page.
Before you place anything
Knowing what a price means does not make a bet a good idea. Set a budget first; the Lower-Risk Gambling Guidelines from the Canadian Centre on Substance Use and Addiction suggest no more than 1% of household income a month and no more than four gambling days a month. Our bankroll management guide turns that into stake sizes, and responsible gambling lists the helpline for your province. Single-event sports betting became lawful for provincially run and licensed operators when the Safe and Regulated Sports Betting Act took effect in 2021; what that means for where you bet is in our guide to sports betting law in Canada.
Quick reference
- Decimal return = stake x odds.
- Minus American = stake to win 100. Plus American = win on 100.
- Implied probability = 1 / decimal odds.
- Add the implied probabilities of every outcome; the excess over 100% is the overround, and 1 - 1/overround is the margin.
- At -110 you need 52.4% winners to break even.
Use the odds converter when you want the arithmetic done for you, and the Canadian betting hub to see which markets are on today.
Sources
- miseojeu.lotoquebec.com/en/home
- playnow.com/sports
- laws-lois.justice.gc.ca/eng/AnnualStatutes/2021_20/page-1.html
- gamblingguidelines.ca
Questions players ask
What does -110 mean in betting?
You stake 110 to win 100 in profit. On a C$11 bet that is C$10 profit and C$21 back in total. In decimal odds -110 is about 1.91.
What does +150 mean?
A 100 stake wins 150 in profit. A C$20 bet at +150 returns C$50: your C$20 back plus C$30 profit. In decimal odds +150 is 2.50.
Which odds format do Canadian sportsbooks use?
Most let you choose. Provincial products such as Loto-Quebec's Mise-o-jeu show decimal odds; offshore books often default to decimal or American and switch in the account settings.
How do I turn odds into a probability?
Divide 1 by the decimal odds. 2.50 gives 40%. For American odds, a minus price is odds / (odds + 100) and a plus price is 100 / (odds + 100).
Why do the probabilities add up to more than 100%?
Because the sportsbook builds its margin into the prices. On a two-way market at -110 both sides, the implied probabilities add up to 104.76%; the extra is the book's edge.