Download the appBy Outlier · Updated
About the Implied Probability Calculator
Implied probability is the win chance needed to break even at given odds, before fees or taxes. Compare it with your own win estimate to see whether the odds may offer value.
How to use this calculator
- Choose an odds format and enter the offered odds.
- Enter a stake to see profit and total payout.
- Enter your own estimated win chance.
- Compare your estimate with the break-even chance. The gap is shown in percentage points.
Formula and definitions
- Break-even win chance = 1 ÷ decimal odds.
- For positive American odds: p = 100 ÷ (A + 100).
- For negative American odds: p = |A| ÷ (|A| + 100).
- Probability edge = your estimate − break-even win chance.
- p
- The break-even win chance as a decimal. Multiply by 100 for a percentage.
- A and |A|
- American odds. |A| means use the number without its minus sign.
- Percentage points
- The gap between two percentages. 55% minus 50% is 5 percentage points.
Worked example
- At -110, the break-even chance is 110 ÷ 210 = 52.38%.
- A 55% win estimate is 2.62 percentage points higher.
- A winning $100 bet earns $90.91 profit and returns $190.91 in total.
How to read your result
The main percentage is the win rate the price requires. It is not the event’s proven chance of winning.
An estimate above that rate suggests an edge only if your estimate is correct.
Assumptions and limitations
- Sportsbook odds include a margin. Win chances across a market can add up to more than 100%.
- This break-even rate applies to bets that win or lose. A push usually returns the stake.
- You supply the win estimate. It does not come from a live Outlier model.
Common mistake to avoid
Do not treat the win chance implied by sportsbook odds as the true chance of the event happening.
Put your result to work
Try a related calculator, or read our sports betting strategy guides to learn more.
- Odds Converter — Odds formats & payout
- No-Vig Fair Odds Calculator — Odds without sportsbook margin
- Expected Value Calculator — Average profit or loss
Implied Probability FAQs
What probability is +200?
+200 is 3.00 in decimal odds. The break-even chance is 1 ÷ 3, or 33.33%.
Why do both sides add up to more than 100%?
The extra amount is called overround. It reflects the sportsbook margin built into the odds. Use the No-Vig Fair Odds Calculator to adjust all sides so they total 100%.
How results are calculated
Results use the formulas and assumptions above. Money is rounded to cents. Odds and percentages are rounded to make them easier to read.
The calculator uses the odds and win chances you enter. It does not load live odds.