Decimal vs American vs Fractional Odds
Last reviewed 24 August 2026 · Written and checked by the bet.ing editorial team
The three formats express the same price differently. Decimal includes your stake and acts as a multiplier (2.50). American shows profit against 100 units (+150). Fractional shows profit against stake (3/2). Decimal is easiest for maths because you can multiply it directly.
Decimal odds
Standard across Europe, Australia and Canada. The number is a multiplier that already includes your stake, so stake × odds is the total return. It handles any price, converts to probability with a single division, and multiplies cleanly for parlays. If you do any calculation at all, work in decimal.
American odds
Standard in the US. A positive number is the profit on a 100-unit stake: +150 wins 150 for a 100 stake. A negative number is the stake needed to win 100: −200 means risking 200 to win 100. The sign flips at even money, which is why there is no price between −100 and +100.
Fractional odds
Traditional in the UK and Ireland, especially horse racing. 5/2 means five units of profit for every two staked. The fraction is reduced to whole numbers, which is why you see prices like 10/11 rather than an exact decimal equivalent.
Converting by hand
- American + to decimal: 1 + odds ÷ 100. +250 → 3.50.
- American − to decimal: 1 + 100 ÷ |odds|. −125 → 1.80.
- Fractional to decimal: 1 + numerator ÷ denominator. 7/4 → 2.75.
- Decimal to American: at 2.00 or above, (decimal − 1) × 100; below 2.00, −100 ÷ (decimal − 1).
| Decimal | American | Fractional | Implied |
|---|---|---|---|
| 1.10 | −1000 | 1/10 | 90.91% |
| 1.33 | −300 | 1/3 | 75.19% |
| 1.50 | −200 | 1/2 | 66.67% |
| 1.80 | −125 | 4/5 | 55.56% |
| 2.00 | +100 | 1/1 | 50.00% |
| 2.75 | +175 | 7/4 | 36.36% |
| 4.50 | +350 | 7/2 | 22.22% |
| 9.00 | +800 | 8/1 | 11.11% |
| 34.00 | +3300 | 33/1 | 2.94% |
Which should you use?
Use whichever your bookmaker displays for placing bets, but convert to decimal whenever you compare prices or estimate value. Comparing 6/4 with +145 in your head invites mistakes; comparing 2.50 with 2.45 does not.
Rounding matters too. Fractional odds are approximations of the underlying price, so a book quoting 10/11 may be running an exact 1.9091. On large stakes that difference is real money.