- Maths reviewed by Josh Miller
- Tested by Diana Westfield
Decimal to American odds splits at 2.00. From 2.00 up, take off 1 and multiply by 100: 2.50 is +150. Under 2.00, divide −100 by the decimal minus 1: 1.80 is −100 ÷ 0.80 = −125. Type a decimal into the free CasinoCalcs converter and it picks the right formula for you.
Decimal to American odds: which formula when
Decimal 2.00 or more: American = +(decimal − 1) × 100 Decimal under 2.00: American = −100 ÷ (decimal − 1)
The split exists because American odds are always built around 100. Favourites tell you what to stake to win 100. Underdogs tell you what 100 wins. At exactly 2.00 the two meet: +100, or −100 if you like, both evens.
Decimal to American odds chart
| Decimal | American | Implied chance |
|---|---|---|
| 1.10 | −1000 | 90.9% |
| 1.20 | −500 | 83.3% |
| 1.25 | −400 | 80.0% |
| 1.33 | −303 | 75.2% |
| 1.40 | −250 | 71.4% |
| 1.50 | −200 | 66.7% |
| 1.57 | −175 | 63.7% |
| 1.67 | −149 | 59.9% |
| 1.80 | −125 | 55.6% |
| 1.91 | −110 | 52.4% |
| 2.00 | +100 | 50.0% |
| 2.10 | +110 | 47.6% |
| 2.20 | +120 | 45.5% |
| 2.50 | +150 | 40.0% |
| 2.75 | +175 | 36.4% |
| 3.00 | +200 | 33.3% |
| 3.50 | +250 | 28.6% |
| 4.00 | +300 | 25.0% |
| 5.00 | +400 | 20.0% |
| 6.00 | +500 | 16.7% |
| 8.00 | +700 | 12.5% |
| 11.00 | +1000 | 9.1% |
Reading the numbers
A minus number that looks small is a short price. −1000 (1.10) means risking C$1,000 to win C$100. A plus number that looks big is long: +800 is a 9.00 shot. If that feels backwards, think of the minus sign as “you pay this much”.
Rounding is the other thing. Odd decimals don’t always land on a neat American number. 1.87 is −114.9, so one site says −115 and another −114. It’s not a different price, just a different rounding rule.
Want the other direction? Here’s the American to decimal converter. To see how much margin is baked into a two-way line, try the no-vig calculator.
Set your limit before you look at the lines. BeGambleAware.org offers free support if you need it.