Matched BetsOdds converter
Convert fractional, decimal and American odds and implied probability. Type in any box and the others update.
Short answer
To convert fractional odds to decimal, divide the top number by the bottom and add 1: 5/2 = 2.5 + 1 = 3.5. To go back, take 1 off the decimal odds and write what's left as a fraction: 3.5 − 1 = 2.5 = 5/2. Decimal odds include your stake, so £10 at 3.5 returns £35 in total.
How to convert odds
Example: 10/11 is 1.9091 in decimal, -110 in American and a 52.38% implied probability. A price of 1.91 on an exchange is exactly 91/100 as a fraction; a bookmaker would quote it as 10/11.
Common odds
| Fractional | Decimal | American | Implied probability |
|---|---|---|---|
| 1/5 | 1.2 | -500 | 83.33% |
| 1/4 | 1.25 | -400 | 80.00% |
| 1/3 | 1.3333 | -300 | 75.00% |
| 2/5 | 1.4 | -250 | 71.43% |
| 1/2 | 1.5 | -200 | 66.67% |
| 4/6 | 1.6667 | -150 | 60.00% |
| 8/11 | 1.7273 | -138 | 57.89% |
| 4/5 | 1.8 | -125 | 55.56% |
| 10/11 | 1.9091 | -110 | 52.38% |
| Evens | 2 | +100 | 50.00% |
| 11/10 | 2.1 | +110 | 47.62% |
| 6/5 | 2.2 | +120 | 45.45% |
| 5/4 | 2.25 | +125 | 44.44% |
| 11/8 | 2.375 | +138 | 42.11% |
| 6/4 | 2.5 | +150 | 40.00% |
| 13/8 | 2.625 | +163 | 38.10% |
| 7/4 | 2.75 | +175 | 36.36% |
| 15/8 | 2.875 | +188 | 34.78% |
| 2/1 | 3 | +200 | 33.33% |
| 9/4 | 3.25 | +225 | 30.77% |
| 5/2 | 3.5 | +250 | 28.57% |
| 11/4 | 3.75 | +275 | 26.67% |
| 3/1 | 4 | +300 | 25.00% |
| 10/3 | 4.3333 | +333 | 23.08% |
| 7/2 | 4.5 | +350 | 22.22% |
| 4/1 | 5 | +400 | 20.00% |
| 9/2 | 5.5 | +450 | 18.18% |
| 5/1 | 6 | +500 | 16.67% |
| 11/2 | 6.5 | +550 | 15.38% |
| 6/1 | 7 | +600 | 14.29% |
| 7/1 | 8 | +700 | 12.50% |
| 8/1 | 9 | +800 | 11.11% |
| 9/1 | 10 | +900 | 10.00% |
| 10/1 | 11 | +1000 | 9.09% |
| 12/1 | 13 | +1200 | 7.69% |
| 14/1 | 15 | +1400 | 6.67% |
| 16/1 | 17 | +1600 | 5.88% |
| 20/1 | 21 | +2000 | 4.76% |
| 25/1 | 26 | +2500 | 3.85% |
| 33/1 | 34 | +3300 | 2.94% |
| 50/1 | 51 | +5000 | 1.96% |
| 100/1 | 101 | +10000 | 0.99% |
Decimal odds rounded to four places and probabilities to two, using the same decimal arithmetic as the Matched Bets app.
What the formats mean
- Fractional (UK): profit compared with stake. 5/2 means £5 profit for every £2 staked. Odds-on prices such as 1/2 pay less than the stake.
- Decimal (Europe and exchanges): total return per £1, stake included. Betting exchanges and matched betting calculators use decimal odds.
- American (moneyline): a plus number is the profit on a 100 stake; a minus number is the stake needed to win 100.
- Implied probability: the chance the price suggests. Add up the implied probabilities of every outcome in a market: anything over 100% is the bookmaker's margin.
Why matched betting uses decimal odds
Exchanges show decimal odds, and the lay stake formulas need them: lay stake = back stake × back odds ÷ (lay odds − commission). Convert the bookmaker's fractional price first, then use the free matched betting calculator or read how to calculate a lay stake. The Matched Bets app has a fractional-to-decimal converter built in.