Implied Probability Explained
Implied probability is the chance of an outcome that a set of odds represents, expressed as a percentage. Convert it from decimal odds with one division: implied probability = 1 ÷ decimal odds. Odds of 2.00 imply a 50% chance; odds of 1.50 imply 66.7%; odds of 4.00 imply 25%.
That single number is the most useful thing you can pull from a price. It tells you what the market thinks, it lets you compare your own estimate against the book's, and — once you add up the implied probabilities across a market — it exposes the bookmaker margin baked into every line. On BETAXIO we measure that margin directly: sampled across 221 markets, Pinnacle averaged a 3.12% margin, while LeoVegas averaged 6.86%. Same events, very different implied probabilities. This guide shows how to read and use the number.
The decimal odds formula
For decimal odds, the conversion is a straight reciprocal:
- Implied probability = 1 ÷ decimal odds
- As a percentage: (1 ÷ decimal odds) × 100
Worked values you'll see on Canadian sportsbooks:
- 1.20 → 1 ÷ 1.20 = 0.833 → 83.3%
- 1.91 → 1 ÷ 1.91 = 0.524 → 52.4%
- 2.50 → 1 ÷ 2.50 = 0.400 → 40.0%
- 3.75 → 1 ÷ 3.75 = 0.267 → 26.7%
- 6.00 → 1 ÷ 6.00 = 0.167 → 16.7%
To reverse it — turn a probability you believe into a fair decimal price — divide 1 by the probability as a decimal. If you rate a team a 45% chance, your fair price is 1 ÷ 0.45 = 2.22. Any price longer than 2.22 is value by your own model.
American and fractional odds
Canadian books display American odds on North American sports (NHL, NBA, NFL, MLB) as often as decimal, so it helps to convert both.
American positive odds (+150): implied probability = 100 ÷ (odds + 100). So +150 → 100 ÷ 250 = 40.0%.
American negative odds (−200): implied probability = |odds| ÷ (|odds| + 100). So −200 → 200 ÷ 300 = 66.7%.
Fractional odds (5/2): implied probability = denominator ÷ (numerator + denominator). So 5/2 → 2 ÷ 7 = 28.6%.
Whatever the display format, the underlying probability is the same number. Decimal 2.50 = American +150 = fractional 3/2 = 40.0% implied. If your sportsbook lets you switch display formats, the implied probability doesn't change — only the presentation does.
Implied Probability Calculator
Why the probabilities in a market add up to more than 100%
Add the implied probabilities of every outcome in a market and you'll get a figure above 100%. That excess is the bookmaker margin (also called the overround or vig).
Take a two-way NHL moneyline priced at 1.91 / 1.91:
- Home implied: 1 ÷ 1.91 = 52.4%
- Away implied: 1 ÷ 1.91 = 52.4%
- Total: 104.8%
The true probabilities can only sum to 100%, so the extra 4.8% is the book's built-in edge. To recover the fair, margin-free probability, divide each implied probability by the market total: 52.4% ÷ 104.8% = 50.0% each.
The margin is exactly why implied probability is not the same as true probability. Every price you see is inflated. The smaller the margin, the closer the implied probability sits to the operator's genuine estimate — and the better the price for you.
How much margin costs you — the BETAXIO data
Margin varies widely between Canadian sportsbooks, and it directly changes the implied probability attached to every line. BETAXIO samples live markets and records the average margin and the best-price share (how often an operator posts the top price in our sample).
Sampled averages:
- Pinnacle — 3.12% average margin, 53.4% best-price share (221 markets)
- FanDuel — 4.06% average margin, 23.5% best-price share (306 markets)
- DraftKings — 4.21% average margin, 54.5% best-price share (898 markets)
- BetMGM — 4.69% average margin, 14.6% best-price share (240 markets)
- Caesars Sportsbook — 5.35% average margin, 36.7% best-price share (784 markets)
- Unibet — 5.74% average margin (201 markets)
- Betway — 6.09% average margin (191 markets)
- BetRivers — 6.28% average margin (280 markets)
- 888sport — 6.63% average margin (251 markets)
- LeoVegas — 6.86% average margin (167 markets)
The practical read: on a two-way market, a 3.12% margin book prices each side near 1.97 where a 6.86% margin book prices it near 1.87. On decimal odds of 1.97 vs 1.87 for a $100 stake, you're leaving roughly $10 of potential return on the table at the higher-margin book on a single winning bet. Over a season, that gap compounds. See live comparisons on our betting odds and market movers pages.
Using implied probability to find value
Value exists when your estimated probability is higher than the odds' implied probability. The method:
1. Estimate the true chance of the outcome yourself (model, form, injuries). 2. Convert the sportsbook price to implied probability with 1 ÷ decimal odds. 3. Strip out the margin if you want the book's fair estimate: implied ÷ market total. 4. Compare. If your probability exceeds the implied probability, the bet has positive expected value.
Worked example. An NBA game lists a team at 2.30.
- Implied probability: 1 ÷ 2.30 = 43.5%
- Your model rates the team a 50% chance.
- Expected value on a $100 stake: (0.50 × $130 profit) − (0.50 × $100 stake) = $65 − $50 = +$15.
A +$15 EV per $100 staked is a strong edge — the kind that only survives at low-margin books, because a wide margin drags the price down and erases it. This is why the operators posting the most best prices in our sample (DraftKings 54.5%, Pinnacle 53.4%, Caesars 36.7%) matter to a value bettor: they leave more of these gaps open. Cross-check prices before you stake using our comparisons and betting tools.
Where the sharpest implied probabilities sit in Canada
Because margin sets how far implied probability drifts from a fair estimate, the low-margin operators produce the most honest numbers. In our sample Pinnacle (3.12%), FanDuel (4.06%) and DraftKings (4.21%) sit at the tight end; 888sport (6.63%) and LeoVegas (6.86%) at the wide end.
Best-price share tells a slightly different story about line-shopping. DraftKings topped the sample at 54.5% and Pinnacle at 53.4%, meaning that on a given market one of those two frequently held the top price. Caesars followed at 36.7% and FanDuel at 23.5%. If you want the implied probability closest to fair on any single bet, checking two or three of these operators before staking is the highest-leverage habit available.
All operators referenced here are licensed by iGaming Ontario for the Ontario market. Availability and legal status differ by province — Ontario runs the AGCO/iGO regime, while other provinces operate their own systems through provincial regulators and lottery corporations. Check what applies where you live. For the full field, see our list of all bookmakers and legal betting sites in Canada.
FAQ
What is implied probability in betting?
It's the probability of an outcome implied by its odds, shown as a percentage. For decimal odds, it equals 1 ÷ the decimal price. Odds of 2.00 imply 50%; odds of 1.25 imply 80%. It reflects the market's estimate plus the bookmaker's margin, not the true probability.
How do I calculate implied probability from decimal odds?
Divide 1 by the decimal odds and multiply by 100. Odds of 3.40 give 1 ÷ 3.40 = 0.294, or 29.4%. That's the whole formula for decimal odds used on Canadian sportsbooks.
Why do the implied probabilities in a market add up to more than 100%?
The excess above 100% is the bookmaker margin (overround or vig). A 1.91 / 1.91 two-way market sums to 104.8%, so the 4.8% is the built-in edge. To get the fair, margin-free probability, divide each side's implied probability by the market total.
How do I convert American odds to implied probability?
For positive odds: 100 ÷ (odds + 100), so +150 = 40.0%. For negative odds: |odds| ÷ (|odds| + 100), so −200 = 66.7%. The result matches the decimal conversion for the same price.
How does implied probability help me find value?
Compare it to your own estimate of the outcome's chance. If you rate a team 50% but the odds imply only 43.5% (a price of 2.30), the bet has positive expected value. Value survives best at low-margin books, since a wide margin lowers the price and closes the gap.
Which Canadian sportsbooks have the lowest margins?
In BETAXIO's sample, Pinnacle averaged the lowest margin at 3.12%, followed by FanDuel at 4.06% and DraftKings at 4.21%. Lower margin means the implied probability sits closer to a fair estimate and the price is better for you. All are licensed by iGaming Ontario for the Ontario market.