- Maths reviewed by Josh Miller
- Tested by Diana Westfield
For American to fractional odds, put the number over 100. +250 becomes 250/100, which simplifies to 5/2. Minus prices go the other way up: −200 becomes 100/200, or 1/2. That’s all the free CasinoCalcs converter is doing, plus snapping the answer to a price a UK bookmaker would actually show.
American to fractional odds, both signs
Plus: fraction = American / 100 (+175 → 175/100 → 7/4) Minus: fraction = 100 / |American| (−125 → 100/125 → 4/5)
−110 is the one everybody asks about. 100/110 simplifies to 10/11, the price that sits on nearly every two-way market. Back it at £11 and you win £10.
+150 is the other common one. It’s 150/100, or 3/2, which UK bookmakers write as 6/4. Same price, they just like their fractions over 4.
American to fractional odds chart
| American | Fractional | Decimal |
|---|---|---|
| −1000 | 1/10 | 1.10 |
| −500 | 1/5 | 1.20 |
| −300 | 1/3 | 1.33 |
| −250 | 2/5 | 1.40 |
| −200 | 1/2 | 1.50 |
| −150 | 4/6 | 1.67 |
| −125 | 4/5 | 1.80 |
| −110 | 10/11 | 1.91 |
| +100 | evens | 2.00 |
| +110 | 11/10 | 2.10 |
| +120 | 6/5 | 2.20 |
| +150 | 6/4 | 2.50 |
| +175 | 7/4 | 2.75 |
| +200 | 2/1 | 3.00 |
| +250 | 5/2 | 3.50 |
| +300 | 3/1 | 4.00 |
| +400 | 4/1 | 5.00 |
| +500 | 5/1 | 6.00 |
| +800 | 8/1 | 9.00 |
| +1000 | 10/1 | 11.00 |
| +2000 | 20/1 | 21.00 |
Rounding odd numbers
Not every American price simplifies nicely. +138 is 138/100, or 69/50, which you’ll never see on a coupon. The nearest standard price is 11/8, and that’s what the converter shows. The decimal underneath tells you the exact value if you need it.
Going the other way, try the fractional to American converter. If you’re comparing prices across sites, the implied probability calculator turns any format into a percentage, which makes the better price obvious.
A better price is still a bet. BeGambleAware.org is free and confidential.