Formulas used
Implied probability = 1 ÷ decimal oddsFair odds = 1 ÷ estimated probabilityEdge = estimated probability − implied probabilityEV = (estimated probability × decimal odds) − 1Free tool
Edge calculator
Measure the gap between your probability estimate and the probability implied by the odds. Compare scenarios to investigate potential value.
Direct answer
Measure the gap between your probability estimate and the probability implied by the odds. Compare prices and explore where your view of a match differs from the market.
Calculator
Calculate the edge
Example in Brazilian football
Imagine a Brasileirão match in the 1x2 market. Your model estimates a 55% chance for the home win, and the best available odds are 2.05.
Implied probability = 1 ÷ 2.05 = 48.78% Fair odds = 1 ÷ 0.55 = 1.82 Edge = 55% − 48.78% = +6.22 p.p. EV = (0.55 × 2.05) − 1 = +12.75%Under this estimate, the offered odds exceed fair value. Compare the match factors, current context, and price movement to investigate the opportunity.
How to use the calculator
- Choose the match market: 1x2, Double Chance, Over 2.5 goals, Both Teams to Score, or Over 9.5 corners.
- Enter your estimated probability.
- Enter the bookmaker's decimal odds, preferably the best available odds.
- See the implied probability, fair odds, edge, and EV.
- Interpret the result as a mathematical comparison, not as a betting instruction.
How to interpret the edge
| Outcome | Reading |
|---|---|
| Positive edge | Your estimated probability is above the implied probability of the odds. There may be value. |
| Edge close to zero | The odds appear close to the fair price. There may not be enough margin. |
| Negative edge | The odds are below the fair price implied by your probability estimate. |
Edge, EV, and fair odds: what's the difference?
| Concept | What it measures |
|---|---|
| Edge | Measures the difference between estimated probability and implied probability. |
| EV | Measures the expected value of the bet considering probability and odds. |
| Fair odds | Shows which odds would be consistent with the estimated probability. |
| Implied probability | Shows the chance the bookmaker's odds are pricing in. |
When to use on Predora.si
On Predora.si, this logic appears when you compare the Active Model's probability with the best odds found among monitored bookmakers. On pages like Upcoming Matches and Upcoming Matches with EV+, the app already cross-references chance, EV, and best odds by market. The calculator serves to understand the math behind the estimated edge and to train your price reading.
This read connects with Active Model, Upcoming Matches with EV+, Upcoming Matches, odds comparison, and AI + Stats / Factors, always as analytical support for football.
Common mistakes
Reading edge without checking its probability estimate.
Using an estimated probability without any criteria.
Comparing odds from different markets or lines.
Ignoring that the odds can change quickly.
Looking at edge without looking at EV.
Ignoring factors, context, league, and sample size.
Treating a high edge as an automatic bet.
Related content
Want to compare this calculation with real football matches?
On Predora.si, you see chance, EV, best odds, and factors by market to compare the scenario with more context.
Explore Predora.siFAQ about the edge calculator
What is edge in betting?
Edge is the difference between the estimated probability for a selection and the implied probability of the bookmaker's odds.
How do you calculate edge with decimal odds?
First calculate the implied probability with 1 ÷ odds. Then do estimated probability − implied probability.
Is positive edge the same as positive EV?
Not exactly. Edge measures the difference in probability. EV measures expected return considering probability and odds. They usually go hand in hand, but they're not the same thing.
What is a good edge?
It depends on the quality of the estimated probability, the market, the odds, and the context. On Predora, the edge appears alongside EV, Factors, market, and Base.
Can I use the calculator for any football market?
Yes, as long as you use the probability and odds from the same market and the same line. The markets covered on Predora are: 1X2, Double Chance, Over 2.5 goals, Both Teams to Score, and Over 9.5 corners.