Odds to Probability Calculator
Convert bookmaker odds into probability, check the total of a market and see the approximate bookmaker margin. The tool works for a single price, a two-way tennis match, a football 1X2 market and any other line where you need the mathematical price of a bet.
For example, 1.80 means roughly 55.56%, 2.00 means 50% and 3.00 means 33.33%. This is not a match prediction — it is the probability that follows from the bookmaker's price.
1.50 → 66.67%
Two in three at the line's price: one of the most common questions about odds of 1.50.
1.80 → 55.56%
A quick check of a single price before you bet.
2.00 → 50%
A nominally even chance before the market margin is taken into account.
1X2 → margin
With three outcomes you see the total percentage and the bookmaker's mark-up.
Work out probability from odds
Enter the bookmaker's odds. For one outcome the calculator shows the probability implied by the price; for two or three outcomes it also shows the market total, the margin and normalised values with the mark-up removed.
Inputs
Results update automatically. Use decimal odds; the decimal separator can be a point or a comma. Fractional and American odds can be converted in the odds converter (linked below).
Result
| Outcome | Odds | Implied | Normalised | No-margin odds |
|---|
Fill in the fields and the result will appear automatically.
When to use this calculator
It is not just for turning odds into percentages as an exercise — the tool helps before you compare prices, check a bookmaker's mark-up or judge whether you have an edge.
Single price
See which percentage corresponds to odds of 1.50, 1.80, 2.20 or 3.00.
Two outcomes
Check tennis, basketball markets without a draw, or a yes/no market.
Three outcomes
Assess a football Home / Draw / Away market and see the bookmaker's mark-up.
For the reverse calculation — from probability to odds, or from stake and payout — use the probability to odds calculator. To compare several bookmakers on the same outcome, line up their prices side by side and convert each one here.
How to convert odds to probability
The basic formula is simple: divide 100 by the decimal odds and you get the probability implied by the bookmaker's price.
Probability (%) = 100 / oddsFor example, 2.00 corresponds to 50%, 1.50 to about 66.67% and 3.00 to about 33.33%. This does not mean the event will happen at exactly that rate: odds reflect the price of the event in the line, not a guaranteed chance.
Odds and probability table
Probability is calculated as 100 / odds. The third column expresses the same thing in words: the number after "1 in" equals the odds themselves; values are rounded.
| Odds | Implied probability | Chance in words |
|---|---|---|
| 1.10 | 90.91% | 1 in 1.10 |
| 1.20 | 83.33% | 1 in 1.20 |
| 1.25 | 80.00% | 1 in 1.25 |
| 1.30 | 76.92% | 1 in 1.30 |
| 1.33 | 75.19% | 1 in 1.33 |
| 1.40 | 71.43% | 1 in 1.40 |
| 1.45 | 68.97% | 1 in 1.45 |
| 1.50 | 66.67% | 1 in 1.50 |
| 1.55 | 64.52% | 1 in 1.55 |
| 1.60 | 62.50% | 1 in 1.60 |
| 1.65 | 60.61% | 1 in 1.65 |
| 1.70 | 58.82% | 1 in 1.70 |
| 1.75 | 57.14% | 1 in 1.75 |
| 1.80 | 55.56% | 1 in 1.80 |
| 1.85 | 54.05% | 1 in 1.85 |
| 1.90 | 52.63% | 1 in 1.90 |
| 1.95 | 51.28% | 1 in 1.95 |
| 2.00 | 50.00% | 1 in 2.00 |
| 2.10 | 47.62% | 1 in 2.10 |
| 2.20 | 45.45% | 1 in 2.20 |
| 2.30 | 43.48% | 1 in 2.30 |
| 2.40 | 41.67% | 1 in 2.40 |
| 2.50 | 40.00% | 1 in 2.50 |
| 2.60 | 38.46% | 1 in 2.60 |
| 2.75 | 36.36% | 1 in 2.75 |
| 3.00 | 33.33% | 1 in 3.00 |
| 3.50 | 28.57% | 1 in 3.50 |
| 4.00 | 25.00% | 1 in 4.00 |
| 5.00 | 20.00% | 1 in 5.00 |
| 6.00 | 16.67% | 1 in 6.00 |
| 8.00 | 12.50% | 1 in 8.00 |
| 10.00 | 10.00% | 1 in 10.00 |
| 15.00 | 6.67% | 1 in 15.00 |
| 20.00 | 5.00% | 1 in 20.00 |
Worked examples for football and tennis
Football 1X2 match
The bookmaker offers: home win 2.20, draw 3.40, away win 3.20. Convert each price into a probability and the total comes out above 100% — that excess is the bookmaker's mark-up.
| Outcome | Odds | Probability | Calculation |
|---|---|---|---|
| Home win (1) | 2.20 | 45.45% | 100 / 2.20 |
| Draw (X) | 3.40 | 29.41% | 100 / 3.40 |
| Away win (2) | 3.20 | 31.25% | 100 / 3.20 |
| Total | — | 106.12% | Margin about 6.12% |
Two-way tennis match
With odds of 1.72 and 2.10 the implied probabilities are roughly 58.14% and 47.62%. They add up to 105.76%, so the mark-up is about 5.76%.
Single price of 1.80
100 / 1.80 = 55.56%. You cannot work out the margin from one outcome, though: it needs the whole market — both players in tennis or all three outcomes in football.
What the bookmaker margin is
The margin (overround) is how far the sum of the probabilities implied by a full market's odds exceeds 100%. It describes the price of the line, not the likely result.
Margin = sum(100 / odds of each outcome) − 100An outcome-by-outcome breakdown and four ways of removing the margin are in the bookmaker margin calculator: the proportional method spreads the mark-up evenly across outcomes, the others shift it towards the outsiders.
What fair, no-margin probabilities are
If the market total is above 100%, it can be scaled back proportionally to 100%. The result is a set of model probabilities without the price mark-up. This is not the objective chance of the event but the output of the normalisation method you chose.
Normalised % = outcome % / market total × 100In the football example above the total is 106.12%. For the home win with its original 45.45%, the proportionally normalised estimate is about 42.83%, and the no-margin odds are 2.33 instead of 2.20. The calculator works these values out automatically for every outcome.
Odds, probability and an edge
Converting odds into probability is the first step towards judging whether you have an edge. A bet makes mathematical sense only when your well-founded estimate of the probability is higher than the one implied by the line.
| Odds | Implied by the line | Your estimate | Initial conclusion |
|---|---|---|---|
| 2.20 | 45.45% | 50% | The bet makes sense if the 50% estimate is well founded. |
| 2.20 | 45.45% | 40% | The odds look too short for that estimate. |
| 1.60 | 62.50% | 70% | Even short odds can be worth a look if your probability estimate is higher. |
Bets like these are known as value bets: the edge exists only when your estimate is better grounded than the market's, and the price is what you test it against.
Related calculators
Bookmaker margin calculator
Why a market adds up to more than 100% and how the price mark-up shapes the odds.
Accumulator calculator
Combined odds, payout and the probability of an acca coming in, plus the margin it builds up.
All calculators
The full set of tools: accumulators, margin, markets, bonuses and limits.
Frequently asked questions
How do I convert odds into probability?
For decimal odds use the formula 100 / odds. For example, 2.00 gives 50%, 1.50 gives 66.67% and 3.00 gives 33.33%.
Do odds show the real probability of an event?
No. Odds set the bookmaker's price, from which you can derive the implied probability. It is not an independent estimate of the event's real chance.
Why do the probabilities in a football match add up to more than 100%?
Because the bookmaker builds in a mark-up. Convert the home, draw and away odds into percentages, add them up, and the total will usually be above 100%.
Can the margin be calculated from a single price?
No. The calculation needs the whole market: two outcomes, three or more. A single price only shows the probability implied by that price.
What is a fair, no-margin probability?
Here it is the proportionally normalised value at which the market totals exactly 100%. It is a model-based way of stripping out the price mark-up, not a proven real-world probability.
Do high odds mean a good chance?
No. Higher odds correspond to a lower implied probability. To decide whether a bet is worth it, you need your own well-founded estimate of the event's probability.
What percentage are odds of 1.50?
66.67% at the line's price: 100 / 1.50. For 1.80 it is 55.56%, for 2.00 exactly 50%, and for 3.00 33.33%. Other values are in the table above.
What percentage is "1 in 25"?
It depends on the notation. "One chance in 25" is 4% and decimal odds of 25.00. Fractional odds of 25/1 mean a win of 25 for every unit staked, on top of the stake: decimal odds of 26.00 and a probability of 3.85%. Fractional and American formats are handled by the odds converter.
Can the calculator find a guaranteed bet?
No. The tool shows the maths of the odds, but it does not guarantee a profit or predict the result.