Free tool
Odds converter
One price, three formats, and the probability it implies.
Decimal (2.50), fractional (6/4) or American (+150, −200). The other two formats appear below.
- Decimal
- 2.50
- Fractional
- 6/4
- American
- +150
- Implied probability
- 40.0%
- bookmaker margin included
- Profit on 1 unit
- 1.50
- stake returned on top
- Return on 1 unit
- 2.50
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Worked example
What is 11/8 in decimal, American and percentage odds?
| Fractional price | 11/8 |
|---|---|
| Decimal: 11 ÷ 8, plus the stake (1) | 2.38 |
| American: (decimal − 1) × 100, as the price is above evens | +138 |
| Implied probability: 1 ÷ decimal | 42.1% |
A 10 stake at 11/8 returns 23.75, a profit of 13.75; the price says the outcome happens 42% of the time, margin included.
The three formats
Decimal odds are the total return on a one-unit stake, stake included: 2.50 returns 2.50 for every 1 staked, a profit of 1.50. They are the standard in Europe, Australia and on exchanges, and they are what every calculation on this site uses, because multiplying a probability by a decimal price gives the expected return directly.
Fractional odds are the profit relative to the stake: 6/4 means a profit of 6 for every 4 staked, so the return on 4 is 10. They are the traditional format in Britain and Ireland. Prices shorter than evens have the larger number second (4/6).
American odds are quoted relative to 100. A positive line is the profit on a 100 stake (+150 wins 150); a negative line is the stake needed to win 100 (−200 needs 200 to win 100). Evens is +100 or −100.
Common prices in every format
The prices bookmakers actually quote, as a fraction, a decimal, an American line and the probability each implies. Decimal prices are rounded to two places, as a coupon shows them.
| Fractional | Decimal | American | Implied probability |
|---|---|---|---|
| 1/10 | 1.10 | -1000 | 90.9% |
| 1/5 | 1.20 | -500 | 83.3% |
| 1/4 | 1.25 | -400 | 80.0% |
| 1/3 | 1.33 | -300 | 75.0% |
| 2/5 | 1.40 | -250 | 71.4% |
| 4/9 | 1.44 | -225 | 69.2% |
| 1/2 | 1.50 | -200 | 66.7% |
| 4/7 | 1.57 | -175 | 63.6% |
| 8/13 | 1.62 | -162 | 61.9% |
| 4/6 | 1.67 | -150 | 60.0% |
| 8/11 | 1.73 | -137 | 57.9% |
| 4/5 | 1.80 | -125 | 55.6% |
| 5/6 | 1.83 | -120 | 54.5% |
| 10/11 | 1.91 | -110 | 52.4% |
| Evens (1/1) | 2.00 | +100 | 50.0% |
| 11/10 | 2.10 | +110 | 47.6% |
| 23/20 | 2.15 | +115 | 46.5% |
| 6/5 | 2.20 | +120 | 45.5% |
| 5/4 | 2.25 | +125 | 44.4% |
| 11/8 | 2.38 | +138 | 42.1% |
| 6/4 | 2.50 | +150 | 40.0% |
| 13/8 | 2.63 | +163 | 38.1% |
| 17/10 | 2.70 | +170 | 37.0% |
| 7/4 | 2.75 | +175 | 36.4% |
| 15/8 | 2.88 | +188 | 34.8% |
| 2/1 | 3.00 | +200 | 33.3% |
| 9/4 | 3.25 | +225 | 30.8% |
| 5/2 | 3.50 | +250 | 28.6% |
| 11/4 | 3.75 | +275 | 26.7% |
| 3/1 | 4.00 | +300 | 25.0% |
| 7/2 | 4.50 | +350 | 22.2% |
| 4/1 | 5.00 | +400 | 20.0% |
| 9/2 | 5.50 | +450 | 18.2% |
| 5/1 | 6.00 | +500 | 16.7% |
| 6/1 | 7.00 | +600 | 14.3% |
| 7/1 | 8.00 | +700 | 12.5% |
| 15/2 | 8.50 | +750 | 11.8% |
| 8/1 | 9.00 | +800 | 11.1% |
| 10/1 | 11.00 | +1000 | 9.1% |
| 12/1 | 13.00 | +1200 | 7.7% |
| 14/1 | 15.00 | +1400 | 6.7% |
| 16/1 | 17.00 | +1600 | 5.9% |
| 20/1 | 21.00 | +2000 | 4.8% |
| 25/1 | 26.00 | +2500 | 3.8% |
| 33/1 | 34.00 | +3300 | 2.9% |
| 50/1 | 51.00 | +5000 | 2.0% |
| 100/1 | 101.00 | +10000 | 1.0% |
What the implied probability tells you
Every price implies a probability: one divided by the decimal price. That figure includes the bookmaker’s margin, so in a three-way market the three implied probabilities add up to something like 105%, not 100%. The bookmaker margin calculator strips that out to show the fair probabilities.
Comparing the implied probability to your own estimate of the chance is the whole of value betting. If you think an outcome is likelier than the price implies, the price is long for you; the expected value calculator puts a number on the gap.
Questions
- How do I convert fractional odds to decimal?
- Divide the first number by the second and add one. 6/4 is 6 ÷ 4 + 1 = 2.50. 10/11 is 10 ÷ 11 + 1 = 1.91.
- How do I convert American odds to decimal?
- A positive line (+150) is the line ÷ 100 + 1, so +150 is 2.50. A negative line (−200) is 100 ÷ the line + 1, so −200 is 1.50.
- What is the probability implied by a price?
- One divided by the decimal price. 2.50 implies 40%. Because the bookmaker builds in a margin, the implied probabilities of every outcome in a market add up to more than 100%.
- How do I turn odds into a percentage?
- Convert to decimal, then divide 100 by it. 6/4 is 2.50, and 100 ÷ 2.50 = 40%. For fractional odds directly: the second number divided by the sum of the two, so 6/4 is 4 ÷ 10 = 40%, and 7/2 is 2 ÷ 9 = 22.2%.
- What is 6/4 in decimal? What about 7/4, 9/4 and 5/4?
- 6/4 is 2.50, 7/4 is 2.75, 9/4 is 3.25 and 5/4 is 2.25. Divide the first number by the second and add one; the table above lists every price a coupon commonly quotes.
- Why does 1.91 show as 10/11 rather than 91/100?
- Bookmakers quote fractional prices from a traditional set and round the decimal equivalent to two places. 10/11 is 1.909, shown as 1.91. The converter gives the simplest fraction that reproduces the decimal price to two places, which is the one you will see on a coupon.
The same numbers on real fixtures
- Where our probabilities disagree most with the prices
- Today’s fixtures with a probability on each prediction
- How the site turns probabilities into fair prices
The model’s probability for every fixture, by market: over 2.5 goals · under 2.5 goals · both teams to score · home wins · all of tomorrow’s matches.
The model does this arithmetic on every price it captures. Members see every pick it publishes, with the price, the stake and the reasoning, from the moment it is published. See what members get →
Other free tools
- Implied probability calculator
What a price says about the chance of an outcome, and the fair price for a probability.
- Bookmaker margin calculator
The overround built into a market, and the fair odds once it is removed.
- Expected value calculator
Whether a price beats your probability, and by how much per unit staked.
- Kelly criterion calculator
A stake sized to the edge, with the fraction and cap we use ourselves.
- Accumulator calculator
Combined odds, returns and the true chance of an accumulator landing.
- Poisson football calculator
Expected goals in, match result, totals, both teams to score and likely scores out.
A calculator turns your numbers into other numbers. It does not know whether your numbers are right, and no arithmetic makes an outcome certain. Never stake money you cannot afford to lose.