Continue with the runnable Python odds tutorial.
Decimal, American, and fractional odds express payout relationships. Convert them to a common unit before comparing prices.
Three ways to describe a return
| Format | Example | Winning return on a 10-unit stake |
|---|---|---|
| Decimal | 2.50 | 25 total |
| American | +150 | 15 profit plus 10 stake |
| Fractional | 3/2 | 15 profit plus 10 stake |
For decimal odds d, implied probability is 1/d. At 2.50 it is 40%. That calculation describes the offered price and its embedded margin.
Preserve the original value
An application should retain source, units, and original numeric strings. Binary probabilities, decimal odds, bids, asks, and executed trade prices represent different observations. Prices with the same numerical value can have different meanings.
Work through an example
Enter +150 in the odds converter, switch to fractional 3/2, and compare the output. Both convert to 2.50. Then use the margin-removal guide to understand why implied probability totals can exceed 100%.
For API representations, see data conventions and the odds response reference. Review settlement compatibility before comparing sources.