What odds are
Odds (in Portuguese law, «cota») are the number your stake is multiplied by. Portuguese law defines fixed-odds betting like this: the odds are a value of 1.00 or more, with up to two decimal places, and the prize is the stake multiplied by those odds (RJO, Art. 4(a)). These are known as decimal odds.
Return and profit
Return = stake × odds.
Example: you stake €10 at odds of 1.85. If the bet wins, you receive 10 × 1.85 = €18.50. That includes your €10, so the profit is €8.50. If it loses, you lose the €10.
Try other amounts in the bet return calculator.
Implied probability
Every price corresponds to a probability: 1 ÷ odds. In a football match with three possible results:
| Result | Odds | Implied probability |
|---|---|---|
| Home win | 1.85 | 54.05% |
| Draw | 3.60 | 27.78% |
| Away win | 4.20 | 23.81% |
| Total | 105.64% |
The numbers are examples for the calculation, not any operator’s prices.
Odds are a price, not a forecast: they tell you what you receive, not what will happen.
Why the total is above 100%
The three results cover every possibility, so the real probabilities add up to exactly 100%. The implied probabilities add up to 105.64%. The extra 5.64% is the operator’s margin: it is why the odds pay less than they would in a market with no margin. The guide Bookmaker margin explains the calculation.
Other formats
On foreign sites you may see fractional odds (17/20) or American odds (−118). They correspond to the same decimal odds of 1.85. The odds converter does the conversion.
Each operator’s rules
Odds change before and during a match. The rules of each bet, including the rules for calculating and paying prizes, must be published on the operator’s site, clearly and kept up to date (RJO, Art. 30(a)). Read them before you bet.
Short odds mean the operator considers the result likely, not that it will happen. In sports betting the result is uncertain by definition (RJO, Art. 4(b)). Only stake what you can afford to lose.
Official sources
- RJO (Annex I to Decree-Law 66/2015), consolidated text published by SRIJ: Arts. 4 and 30 (Portuguese)Checked 15/10/2026
- SRIJ · Direitos e deveres do jogador (player rights and duties, Portuguese)Checked 15/10/2026
Frequently asked questions
Does the return include my stake?
Yes. With decimal odds the return already includes the stake: €10 at 1.85 returns €18.50, of which €8.50 is profit. If the bet loses, you lose the €10.
What do odds of 1.00 mean?
That is the minimum value set by law (RJO, Art. 4(a)). At 1.00 the return equals the stake: there is no profit.
Is the implied probability the real probability?
No. It is the probability the price suggests, with the operator’s margin already included. Nobody knows the real probability of a sporting result.