Every price on a sportsbook answers two questions: how much you get back if you win, and how likely the book thinks the outcome is. The answer comes in three formats. Decimal (2.50), American (+150) and fractional (3/2) look nothing alike and say exactly the same thing. Learn to read all three and you can compare any price anywhere, and spot what the bookmaker keeps for itself. Here’s how each format works, how to convert between them, and the one conversion that matters most: from odds to probability.
- Decimal: total return per C$1, stake included. 2.50 turns C$10 into C$25.
- American: + is profit on C$100; - is the stake needed to win C$100.
- Fractional: profit per unit staked. 3/2 means C$3 profit per C$2.
- Implied probability = 1 / decimal odds. 2.50 implies 40%.
Decimal odds
Decimal odds tell you the total you get back for every C$1 staked, including the stake itself. That makes them the cleanest format for maths, and it’s the format Canadian provincial sites display: Mise-o-jeu prices every selection in decimal, and PlayNow Sports has an “Odds 101” page and an odds calculator for the same reason.
Formula: return = stake x decimal odds. Profit = return - stake.
Worked example, illustrative numbers: C$20 at 1.80 returns C$36, so C$16 is profit. C$20 at 3.40 returns C$68, so C$48 is profit. Anything under 2.00 means the book sees the outcome as more likely than not; anything over 2.00, less likely. Exactly 2.00 is a coin flip with no margin, which you’ll rarely see.
American odds
American odds (also called moneyline odds) use C$100 as the pivot, and the sign tells you which way to read them.
- Positive (+150): the profit on a C$100 stake. +150 means C$100 wins C$150 in profit, C$250 back in total.
- Negative (-110): the stake you need to win C$100 in profit. -110 means you stake C$110 to win C$100, C$210 back in total.
You don’t have to bet C$100; the ratio scales. C$22 at -110 wins C$20. C$10 at +250 wins C$25. Even money shows as +100, which is 2.00 in decimal. American odds are common on North American sportsbooks and in sports media, so you’ll see them on NHL, NFL and NBA coverage even if your book shows decimals.
Fractional odds
Fractional odds give the profit per unit staked, as a fraction. 3/2 (“three to two”) means C$3 profit for every C$2 bet. 10/11 means C$10 profit for every C$11, which is the same price as -110. 1/1 is “evens”. They’re traditional in British horse racing and golf, and some books still use them for futures and each-way markets.
Formula: decimal = 1 + (top number / bottom number). So 5/1 is 6.00 and 4/6 is about 1.67.
The conversion table
Here are the most common prices in all three formats, with what each implies.
| 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 (even) | 1/1 (evens) | 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% |
Computed by BonusMadness from the standard conversion formulas below, October 2026.
🧮 The conversion formulas
| Conversion | Formula |
|---|---|
| American to decimal | Positive: 1 + American / 100. Negative: 1 + 100 / (American without the minus) |
| Decimal to American | 2.00 or more: +(decimal - 1) x 100. Under 2.00: -100 / (decimal - 1) |
| Fractional to decimal | 1 + top / bottom |
| Decimal to fractional | decimal - 1, written as a simple fraction |
Worked example: -110 to decimal is 1 + 100/110 = 1.909, shown as 1.91. And 2.50 to American is +(2.50 - 1) x 100 = +150. Rounding is why a book may show 1.91 in one format and -110 in another and both are right. If you’d rather skip the arithmetic, our odds converter flips any price between all three formats and shows the implied probability.
Implied probability: what counts
Converting between formats is housekeeping. The real skill is turning a price into a probability.
Formula: implied probability = 1 / decimal odds. For American odds: positive, 100 / (odds + 100); negative, odds / (odds + 100), using the number without the minus.
So +150 implies 100 / 250 = 40%. -110 implies 110 / 210 = 52.4%. Once a price is a percentage, you can compare it to your own view. If you think a team wins 45% of the time and the price implies 40%, the price is generous by your estimate. If you think 35%, it’s short. That comparison is the core of every betting decision, and it’s the part no format change can do for you.
🧮 Implied probability by decimal odds
| 1.25 (-400) | 80.0% |
|---|---|
| 1.50 (-200) | 66.7% |
| 1.91 (-110) | 52.4% |
| 2.00 (+100) | 50.0% |
| 2.50 (+150) | 40.0% |
| 3.00 (+200) | 33.3% |
| 4.00 (+300) | 25.0% |
| 6.00 (+500) | 16.7% |
| 11.00 (+1000) | 9.1% |
Why it all adds up past 100%
Take a hockey game priced at -110 on both sides of the puck line. Each side implies 52.38%. Together, 104.76%. No game has a 104.76% chance of producing a result; the extra 4.76 points is the bookmaker’s built-in edge, called the overround. Converted to a margin, it means the book keeps about 4.55% of the money on that market if the betting is balanced.
That’s why the odds on both sides of a “50-50” game are both under 2.00. A fair coin flip would be 2.00 each way. The gap between 2.00 and 1.91 is the price of the bet. Our bookmaker margin guide shows how to calculate it on any market, including three-way hockey lines and futures, where it gets bigger.
Odds and the bets you’ll actually place
Odds formats work the same on every bet type, but some bets stack prices in ways worth knowing.
- Moneyline, spread and totals: single prices, read exactly as above. Our bet types guide covers what each one settles on.
- Parlays: the decimal odds of each leg multiply. Three legs at 1.91 make about 6.96. The implied probabilities multiply too, so the chance of landing all three drops to about 12.5% on true coin flips. The parlay guide and the parlay calculator run the numbers.
- Live bets: prices move with the game. The format doesn’t change, but you have seconds to read it. The live betting guide covers what that does to your decisions.
- Free bets: a C$10 free bet at 3.00 returns C$20, not C$30, because the stake isn’t paid back. Our free bets guide explains the maths.
Why odds move
A price isn’t fixed once it’s posted. Books adjust odds as news lands (an injured starter, a goalie change, weather) and as money comes in on one side. Mise-o-jeu’s page says it plainly: Loto-Quebec may modify the odds at any time and at its discretion. Offshore books reprice the same way.
Two practical consequences. First, the price you get is the price at the moment your bet is accepted, so a slip that sat in your cart for ten minutes may be rejected or repriced. Second, the same game can carry different odds at different books at the same moment. Converting each price to implied probability shows which one is cheaper. Over a season of bets, picking the better number a few points at a time can add up to more than a bonus is worth, which is why our guide to choosing a sportsbook puts pricing near the top.
Odds on Canadian provincial sites
Provincial products show prices in decimal, and they stack them the standard way. Mise-o-jeu lets you register a single selection or combine several, with the odds of each selection multiplied together. Sport Select, sold on paper slips in the Prairies and the territories, runs Pro-Line, point spread, over/under, props, futures and pools, with wagers from $2 to $100. The maths in this guide applies to all of them, and to offshore books licensed outside Canada. Our law guide explains who runs which product in each province.
Common mistakes with odds
- Reading -110 as a 110% return. It’s a stake of C$110 to win C$100, or about 91 cents profit per dollar.
- Comparing formats across books without converting. A 1.95 at one book beats -110 at another; convert first.
- Treating short odds as safe. 1.25 still loses one time in five on its own implied probability.
- Forgetting the margin in the probability. Implied probabilities include the book’s edge, so the “real” chances are a little lower than the prices suggest.
🍁 Before you bet in Canada
Reading odds well tells you what a bet costs. It doesn’t make any outcome more likely. The sports betting guide covers how betting works outside Ontario and Alberta, and the betting hub is the place to start comparing. Everything we cover is for players aged 19 or over outside Ontario and Alberta. Set a stake limit before you bet, and see our responsible gambling page for every provincial helpline.
FAQ
What does -110 mean in betting odds?
It's American odds for a favourite-style price: you stake C$110 to win C$100 in profit. In decimal that's 1.91, and the implied probability is 52.4%. It's the standard price on both sides of many spreads and totals, which is where the bookmaker's margin comes from.
What do decimal odds of 2.50 mean?
Every C$1 staked returns C$2.50 if the bet wins, stake included. A C$10 bet returns C$25, which is C$15 in profit. The implied probability is 1 divided by 2.50, or 40%. Decimal odds are the format Canadian provincial sites such as Mise-o-jeu use.
How do I convert American odds to decimal?
For positive 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. Our odds converter does it instantly for any price.
What is implied probability?
It's the chance of an outcome that a price represents. For decimal odds, it's 1 divided by the odds, so 4.00 implies 25%. Add the implied probabilities of every outcome in a market and you'll get more than 100%; the excess is the bookmaker's margin.
Which odds format is best?
They all describe the same price, so none gives better value. Decimal is the easiest for maths because the stake is already included, which is why we use it in our guides. Most sportsbooks let you switch formats in the account settings.
