How betting odds work: decimal odds and implied probability
Quick answer: Odds show how much a bet pays and the implied chance of an outcome. In decimal odds, your return = stake × odds, and the implied probability =...
Quick answer: Odds show how much a bet pays and the implied chance of an outcome. In decimal odds, your return = stake × odds, and the implied probability = 1 ÷ odds. Bookmakers add a margin, so the implied probabilities add up to more than 100%.
Decimal odds and implied probability
| Decimal odds | Implied probability | €10 returns |
|---|---|---|
| 1.50 | 66.7% | €15.00 |
| 2.00 | 50.0% | €20.00 |
| 2.50 | 40.0% | €25.00 |
| 3.00 | 33.3% | €30.00 |
| 5.00 | 20.0% | €50.00 |
| 10.00 | 10.0% | €100.00 |
The bookmaker’s margin
If a fair coin flip were priced fairly it would be 2.00 / 2.00 (50% each). Bookmakers shorten this (e.g. 1.90 / 1.90) so the implied probabilities exceed 100% — that gap is the margin, or ‘overround’, and it is how they profit. Comparing odds and avoiding heavy-margin markets improves long-term value.
Frequently asked questions
- How do I calculate my winnings from decimal odds?
- Multiply your stake by the decimal odds. A €10 bet at 2.50 returns €25 in total (€15 profit plus your €10 stake).
- What is implied probability?
- The chance of an outcome implied by the odds: 1 ÷ decimal odds. Odds of 4.00 imply a 25% chance.
- Why don’t the probabilities add up to 100%?
- Because the bookmaker builds in a margin (overround). The total exceeds 100%, which is the operator’s built-in edge.
- Are higher odds better?
- Higher odds pay more but imply a lower chance of winning. ‘Value’ is when you judge the real chance to be higher than the odds suggest.
Related guides
Our editorial team monitors regulated betting markets across West Africa with a focus on GCG licensing, mobile money payment methods and responsible gambling compliance. This MSport Ghana guide is based on publicly available GCG licensing data, official MSport product pages, partnership announcements and cross-referenced third-party research. We are not affiliated with MSport or Mobile Sport Group. This is an independent editorial guide. Always verify current terms at msport.com/gh/web.