Odds, Probability & Bankroll
Odds to percentage chart
An odds to percentage chart is a conversion table that shows the implied probability of an event as a percentage, given a set of odds.
- Formula
- For fractional odds (a/b), implied probability = b / (a + b) × 100%
- 1/1 odds
- 50% implied probability
- 4/1 odds
- 20% implied probability
Key points
- The chart uses a fixed formula, not estimation, to convert odds into an implied percentage chance of winning or breaking even.13
- For fractional odds of 1/1, the implied probability is 50%; for 4/1, it is 20%.
- Odds range from 0 to infinity, while probability is bounded between 0% and 100%.12
Where this term is used
Related terms
Odds & probability
Odds payout chart
Shows potential profit for a given stake, rather than implied probability.
Odds & probability
Odds
The ratio of event probability to non-event probability, which the chart converts into a percentage.
Odds & probability
Betting odds
The quoted odds from a bookmaker, which the chart translates into implied probability.
Odds & probability
Fractional odds to decimal
A different conversion format for odds, not directly into percentage.
Odds & probability
Odds vs probability
Explains the difference between odds and probability, which the chart bridges.
Odds & probability
American odds
A format that uses positive and negative numbers, requiring a different conversion formula.
Sources
- Odds en.wikipedia.org Defines odds and the formula for converting odds to probability.
- Statistical notes for clinical researchers: Definition and comparison of risk and odds pmc.ncbi.nlm.nih.gov Explains the range of odds versus probability.
- Conflict Of Interest pmc.ncbi.nlm.nih.gov Provides the formula p = odds / (1 + odds) for conversion.
Sources are drawn from regulators, universities and published research, and each one is labelled with what it actually is — a preprint is not called a paper. Bookmaker and affiliate pages are never cited here, because a page that sells betting is not a neutral authority on it.