Start with a $20 example
Imagine a head-to-head bet on the footy at 2.50. A hypothetical $20 stake would return $50 if your team wins. That is not $50 profit: $20 of it is your original stake.
Change the example below and watch the return and profit separately. You do not need an account, and nothing is placed with a bookie.
The payout and implied-probability definitions are set out in Sportsbet’s odds guide. The price still does not establish the actual chance of winning.
How decimal odds work
A $20 bet at 2.50 returns $50 if it wins. That includes the original $20 stake, so the profit is $30. If it loses, the return is $0 and the loss is $20.
| Example stake | Decimal odds | Return if it wins | Profit if it wins |
|---|---|---|---|
| $20 | 1.50 | $30 | $10 |
| $20 | 2.00 | $40 | $20 |
| $20 | 2.50 | $50 | $30 |
These are hypothetical examples for an ordinary win or loss. Fees, commission, dead heats, deductions and other settlement rules can change the amount paid.
What is implied probability?
The calculation is 100 ÷ decimal odds.
| Decimal odds | Implied probability |
|---|---|
| 1.50 | 66.67% |
| 2.00 | 50% |
| 2.50 | 40% |
| 4.00 | 25% |
At 2.00, the implied probability is 50%. That is what the price says, not a promise that the team wins every second game. The bookie’s margin and the way the market is priced are part of the number.
What is bookmaker margin?
For a market with every possible outcome included, add the implied probabilities. The amount above 100% is commonly called the overround.
In a hypothetical two-outcome market priced at 1.90 on both sides:
- Each side implies approximately 52.63%.
- Together they imply approximately 105.26%.
- The overround is approximately 5.26 percentage points.
That is a description of the quoted market, not a prediction of the bookmaker's realised profit. The allocation of stakes, results and settlement matter too. Removing margin also requires assumptions; it does not reveal an outcome's true probability.
Does a short price mean a safe bet?
No. Shorter odds imply a higher chance than longer odds, but the selection can still lose. A favourite is the market's shortest-priced option, not a guaranteed winner.
It is also possible to take a worse price on a likely winner. Price and probability are different questions. The expected value guide explains how they relate.
The next useful check
Once the payout makes sense, check that two prices are for the same bet. A team to win in regular time and a team to win including extra time can settle differently. The team name alone is not enough.
Use the odds comparison calculator to see how two entered prices change the return. Read how line shopping works for the practical checks.