Implied Probability Calculator
Convert decimal odds into implied probability, calculate fair odds from your own estimate and compare the difference with the market.
Calculator inputs
How to use the implied probability calculator
This calculator converts decimal odds into implied probability and converts your own probability estimate back into fair decimal odds. It also shows the complement probability and makes it easier to compare your estimate with the market price.
Enter decimal odds above 1.00 and a probability between 0 and 100%. The calculator performs both conversions at the same time. The figures are mathematical references, not predictions or guarantees.
What is implied probability?
Implied probability is the percentage represented by betting odds. It converts a market price into a probability-like figure, making it easier to compare prices and understand the break-even point of a bet.
For example, decimal odds of 2.00 imply 50%. Decimal odds of 1.50 imply 66.67%, while odds of 3.00 imply 33.33%.
Price converted
Odds are translated into a percentage that is easier to interpret.
Break-even reference
The percentage shows the approximate win rate required to break even before costs.
Not true probability
The figure can include bookmaker margin and may differ from the real chance of the outcome.
Implied probability formula
For decimal odds, implied probability is calculated by dividing 100 by the decimal price.
100 ÷ Decimal oddsWith decimal odds of 1.80:
100 ÷ 1.80 = 55.56%This means a bettor would need to win approximately 55.56% of comparable bets at odds of 1.80 to break even before margin, taxes or fees.
What are fair odds?
Fair odds are the decimal odds corresponding to a probability estimate without bookmaker margin. They are calculated by dividing 100 by the probability percentage.
100 ÷ Probability percentageIf your estimate is 55%, the fair decimal odds are approximately 1.82. If the market offers 1.95, the available price is higher than your fair-price estimate. If the market offers 1.70, the price is shorter than your estimate suggests.
Break-even probability
Break-even probability is the win rate required for a price to produce zero long-run profit before costs. For decimal odds, it is the same basic figure as implied probability.
| Decimal odds | Break-even probability |
|---|---|
| 1.50 | 66.67% |
| 1.80 | 55.56% |
| 2.00 | 50.00% |
| 2.50 | 40.00% |
| 3.00 | 33.33% |
Bookmaker margin and overround
Bookmakers usually build margin into their odds. In a complete market, the implied probabilities of all outcomes may add up to more than 100%. The amount above 100% is commonly called overround.
For example, if both sides of a two-outcome market are priced at 1.91, each side implies about 52.36%. Together they total approximately 104.72%, suggesting an overround of about 4.72%.
Total implied probability − 100%This calculator uses one price at a time, so it does not remove margin from an entire market. To estimate no-vig probabilities, you need every outcome price.
Implied probability examples
| Decimal odds | Implied probability | Your probability | Fair odds | Difference |
|---|---|---|---|---|
| 1.80 | 55.56% | 55% | 1.82 | -0.56 pts |
| 2.10 | 47.62% | 52% | 1.92 | +4.38 pts |
| 2.50 | 40.00% | 42% | 2.38 | +2.00 pts |
| 1.50 | 66.67% | 64% | 1.56 | -2.67 pts |
Example 1: market probability above your estimate
Odds of 1.80 imply 55.56%. If you estimate the true chance at 55%, your estimate is slightly below the market-implied figure. Your fair odds are approximately 1.82.
Example 2: your estimate above the market
Odds of 2.10 imply 47.62%. If your estimate is 52%, your probability is 4.38 percentage points higher than the market-implied figure. This may indicate theoretical value, but only if the estimate is reliable.
Complement probability
The complement is the probability that the selected outcome does not occur. It is calculated as 100% minus the implied probability.
100% − Implied probabilityIf odds imply 55.56%, the complement is 44.44%.
Probability versus prediction
A probability estimate expresses uncertainty. It does not say that an outcome will definitely occur. A 60% selection can lose, while a 30% selection can win. Probabilities are useful because they describe expected frequency over repeated events, not certainty in one match.
Common implied probability mistakes
- Treating implied probability as true probability. The price may include margin.
- Ignoring the other outcomes in the market. Overround can only be assessed using all prices.
- Confusing percentage points with percent change. A move from 40% to 45% is five percentage points.
- Rounding too early. Small rounding differences can affect fair-odds comparisons.
- Assuming a higher probability always means better value. Value depends on both probability and price.
- Using probability estimates without calibration. Estimates should be reviewed against real results over time.
Implied probability and value betting
Comparing your probability estimate with market-implied probability is the starting point for value analysis. If your estimate is higher than the implied percentage, the price may be attractive. If your estimate is lower, the market price may be too short.
The next step is expected-value analysis, which combines probability and odds into one figure. Use the Value Bet Calculator for that comparison.
Related probability and value guides
Convert the price, then evaluate the estimate
Implied probability is a starting point. Explore the Academy for value betting, bookmaker margin, variance and bankroll-management guidance.
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Implied Probability Calculator FAQ
What is implied probability?
Implied probability is the percentage represented by betting odds.
How do I calculate implied probability from decimal odds?
Divide 100 by the decimal odds.
How do I calculate fair decimal odds?
Divide 100 by your probability percentage.
What is break-even probability?
It is the approximate win rate required to break even at a given price before costs.
Why can market probabilities total more than 100%?
Because bookmaker margin is built into the prices.
What is bookmaker overround?
It is the amount by which the total implied probability of all outcomes exceeds 100%.
Does implied probability equal true probability?
No. It is derived from price and may include margin or market error.
What is complement probability?
It is 100% minus the implied probability.
Can I enter probabilities above 100%?
No. Probability must be above 0% and below 100%.
Are fair odds guaranteed to be available?
No. Fair odds are a mathematical benchmark based on an estimate.
Can two people calculate different fair odds?
Yes. Different probability estimates produce different fair odds.
Can implied probability identify value?
It can support value analysis when compared with a reliable personal probability estimate.
Does this calculator remove bookmaker margin?
No. Removing margin requires all outcome prices in the market.
Is my data stored?
No. The calculation runs locally in your browser and requires no registration.
Can implied probability predict the match result?
No. It translates price into percentage and does not predict a guaranteed outcome.