Odds Converter
Type a price into any box — fractional (5/2), decimal (3.5), American (+250) or implied probability (28.57%) — and the other three update straight away. Fractional results snap to a standard UK price when the decimal matches one; otherwise the converter shows the simple fraction and marks it ≈ (not a standard price).
How to convert odds by hand
| Conversion | Formula | Example |
|---|---|---|
| Fractional to decimal | (first number ÷ second number) + 1 | 5/2 → 2.5 + 1 = 3.5 |
| Decimal to fractional | decimal − 1, written as a fraction | 3.5 − 1 = 2.5 = 5/2 |
| Decimal to American, 2.0 or more | (decimal − 1) × 100, with a + sign | 3.5 → +250 |
| Decimal to American, below 2.0 | −100 ÷ (decimal − 1) | 1.5 → −200 |
| American (+) to decimal | 1 + (American ÷ 100) | +150 → 2.5 |
| American (−) to decimal | 1 + (100 ÷ the number without its minus sign) | −200 → 1.5 |
| Decimal to implied probability | 100 ÷ decimal | 3.5 → 28.6% |
| Fractional to implied probability | second number ÷ (first + second) × 100 | 5/2 → 2 ÷ 7 = 28.6% |
Odds conversion table
Standard UK fractional prices and their equivalents, generated from the same conversion code as the converter above. Decimal odds are rounded to two places.
| Fractional | Decimal | American | Implied probability |
|---|---|---|---|
| 1/10 | 1.10 | −1000 | 90.9% |
| 1/9 | 1.11 | −900 | 90.0% |
| 1/8 | 1.13 | −800 | 88.9% |
| 1/7 | 1.14 | −700 | 87.5% |
| 2/13 | 1.15 | −650 | 86.7% |
| 1/6 | 1.17 | −600 | 85.7% |
| 2/11 | 1.18 | −550 | 84.6% |
| 1/5 | 1.20 | −500 | 83.3% |
| 2/9 | 1.22 | −450 | 81.8% |
| 1/4 | 1.25 | −400 | 80.0% |
| 2/7 | 1.29 | −350 | 77.8% |
| 3/10 | 1.30 | −333.33 | 76.9% |
| 1/3 | 1.33 | −300 | 75.0% |
| 4/11 | 1.36 | −275 | 73.3% |
| 2/5 | 1.40 | −250 | 71.4% |
| 4/9 | 1.44 | −225 | 69.2% |
| 1/2 | 1.50 | −200 | 66.7% |
| 8/15 | 1.53 | −187.5 | 65.2% |
| 4/7 | 1.57 | −175 | 63.6% |
| 8/13 | 1.62 | −162.5 | 61.9% |
| 4/6 | 1.67 | −150 | 60.0% |
| 8/11 | 1.73 | −137.5 | 57.9% |
| 4/5 | 1.80 | −125 | 55.6% |
| 5/6 | 1.83 | −120 | 54.5% |
| 10/11 | 1.91 | −110 | 52.4% |
| Evens | 2.00 | +100 | 50.0% |
| 11/10 | 2.10 | +110 | 47.6% |
| 6/5 | 2.20 | +120 | 45.5% |
| 5/4 | 2.25 | +125 | 44.4% |
| 11/8 | 2.38 | +137.5 | 42.1% |
| 6/4 | 2.50 | +150 | 40.0% |
| 13/8 | 2.63 | +162.5 | 38.1% |
| 7/4 | 2.75 | +175 | 36.4% |
| 15/8 | 2.88 | +187.5 | 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% |
| 10/3 | 4.33 | +333.33 | 23.1% |
| 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% |
| 11/2 | 6.50 | +550 | 15.4% |
| 6/1 | 7.00 | +600 | 14.3% |
| 13/2 | 7.50 | +650 | 13.3% |
| 7/1 | 8.00 | +700 | 12.5% |
| 15/2 | 8.50 | +750 | 11.8% |
| 8/1 | 9.00 | +800 | 11.1% |
| 17/2 | 9.50 | +850 | 10.5% |
| 9/1 | 10.00 | +900 | 10.0% |
| 10/1 | 11.00 | +1000 | 9.1% |
| 11/1 | 12.00 | +1100 | 8.3% |
| 12/1 | 13.00 | +1200 | 7.7% |
| 14/1 | 15.00 | +1400 | 6.7% |
| 16/1 | 17.00 | +1600 | 5.9% |
| 18/1 | 19.00 | +1800 | 5.3% |
| 20/1 | 21.00 | +2000 | 4.8% |
| 22/1 | 23.00 | +2200 | 4.3% |
| 25/1 | 26.00 | +2500 | 3.8% |
| 28/1 | 29.00 | +2800 | 3.4% |
| 33/1 | 34.00 | +3300 | 2.9% |
| 40/1 | 41.00 | +4000 | 2.4% |
| 50/1 | 51.00 | +5000 | 2.0% |
| 66/1 | 67.00 | +6600 | 1.5% |
| 80/1 | 81.00 | +8000 | 1.2% |
| 100/1 | 101.00 | +10000 | 1.0% |
| 125/1 | 126.00 | +12500 | 0.8% |
| 150/1 | 151.00 | +15000 | 0.7% |
| 200/1 | 201.00 | +20000 | 0.5% |
| 250/1 | 251.00 | +25000 | 0.4% |
What implied probability means
Implied probability turns a price into a percentage: the chance of the outcome that the odds suggest. Odds of 5/2 (3.5) imply 100 ÷ 3.5 = 28.6%. It is a reading of the price, not the real chance of the outcome — nobody knows that in advance — and it includes the bookmaker’s margin.
The bookmaker’s margin (overround)
Add up the implied probabilities of every outcome in a market and the total comes to more than 100%. The amount over 100% is the overround: the margin built into the prices, which gives the bookmaker its edge.
As an illustration, a two-way market priced at 10/11 on each side implies 52.4% + 52.4% = 104.8%, an overround of about 4.8%. If stakes came in on each side in proportion to those prices, the bookmaker would keep about 4.5% of everything staked, whichever side won. Over many bets, the margin means bettors as a group get back less than they stake. That is the cost of betting, and why it is best treated as paid-for entertainment rather than a way to make money.
Other calculators
- Bet calculator — returns on singles, accumulators and full-cover bets.
- Each way calculator — win and place parts, Rule 4 and dead heats.
- Lucky 15 calculator — all 15 bets on four selections.
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Frequently asked questions
What does 5/2 mean?
5/2, said “five to two”, means you would win £5 for every £2 staked, plus your stake back, if the bet wins. A £2 bet at 5/2 returns £7 in total. In decimal it is 3.5, in American odds +250, and its implied probability is 28.6%.
What are evens?
Evens (also written evs, 1/1 or 2.0) means the winnings equal the stake: £10 at evens returns £20 if it wins, including your £10 stake. It is +100 in American odds and implies a 50% chance.
How do I convert fractional odds to decimal?
Divide the first number by the second and add 1. For example, 5/2 becomes 2.5 + 1 = 3.5, and 10/11 becomes about 1.91. Evens is 2.0.
What do plus and minus mean in American odds?
A plus number is what a 100 stake would win: +250 wins 250 on a 100 stake, the same as 5/2. A minus number is what you would need to stake to win 100: −200 means staking 200 to win 100, the same as 1/2.
Why is a fraction marked ≈?
UK bookmakers usually quote fractional odds from a standard set of prices, such as 10/11, 11/8 and 5/2. If the price you enter is not close to one of them, the converter shows the nearest simple fraction instead and marks it ≈.