Fractional odds are the British and Irish racing default; American odds are the U.S. moneyline default. Whether you are a UK punter checking the U.S. price of an NFL game or a U.S. bettor browsing a Cheltenham card, this converter flips between formats. The math runs through decimal odds as an intermediate step.
Quick example: 3/2 (fractional) = +150 (American). Use the calculator below for any value, or scroll for the full conversion table.
Two formulas, depending on whether the fraction is greater than or less than 1/1 (Evens):
American = (Numerator / Denominator) × 100American = −100 × (Denominator / Numerator)Common odds across all three formats. Use this as a quick reference; the calculator above handles any value to four decimal places of precision.
| Decimal | American | Fractional |
|---|---|---|
| 1.10 | -1000 | 1/10 |
| 1.25 | -400 | 1/4 |
| 1.40 | -250 | 2/5 |
| 1.50 | -200 | 1/2 |
| 1.67 | -150 | 4/6 |
| 1.75 | -133 | 3/4 |
| 1.83 | -120 | 5/6 |
| 1.91 | -110 | 10/11 |
| 2.00 | +100 | 1/1 (Evens) |
| 2.10 | +110 | 11/10 |
| 2.25 | +125 | 5/4 |
| 2.50 | +150 | 6/4 |
| 3.00 | +200 | 2/1 |
| 3.50 | +250 | 5/2 |
| 4.00 | +300 | 3/1 |
| 5.00 | +400 | 4/1 |
| 6.00 | +500 | 5/1 |
| 11.00 | +1000 | 10/1 |
| 21.00 | +2000 | 20/1 |
| 51.00 | +5000 | 50/1 |
| 101.00 | +10000 | 100/1 |
Fractional odds are the standard at British and Irish high-street bookies, racecourses, and racing broadcasts. They map directly to "win N per M staked" and remain the preferred format for many UK racing punters.
American odds are the U.S. sportsbook standard and the language of U.S. sports media. If you are watching a U.S. game or browsing a U.S. site, every price will be in this format.
1/1 = +100 in American — even money, 50% implied probability. A $100 bet returns $200 total.
5/2 = 2.5 × 100 = +250 in American. A $100 bet returns $350 total ($250 profit).
1/4 → −100 × 4 = −400 in American. A $400 bet returns $500 total ($100 profit).
−110 American corresponds to fractional 10/11 — an odds-on price where you risk 11 to win 10. Decimal equivalent is 1.909. Note the inversion: fractional 11/10 (slight underdog, decimal 2.10) is +110 American, not −110. Direction of the fraction matters.