Implied probability, defined with a worked example
Implied probability is the chance that a price suggests: one divided by the decimal odds. Odds of 3.20 give 1 ÷ 3.20 = 0.3125, or 31.25%. The figure includes the bookmaker's margin, so it is not the true chance of the result. This page defines the term, shows the arithmetic and links to the margin and expected value pages.
The definition and the formula
Implied probability = 1 ÷ decimal odds. Multiply by 100 to read it as a percentage.
Decimal odds state the total return per unit staked, including the stake. A price of 3.20 returns A$3.20 for each A$1 staked on a win. Working backwards, the price implies a 31.25% chance.
This site states odds in decimal form. Whether each operator shows them that way is read from its own pages and is not confirmed on 2026-11-13.
Where this stands: one formula, 1 ÷ odds, turns a decimal price into a percentage.
Five conversions
| Decimal odds | Working | Implied probability |
|---|---|---|
| 1.50 | 1 ÷ 1.50 = 0.6667 | 66.67% |
| 2.00 | 1 ÷ 2.00 = 0.5000 | 50.00% |
| 3.20 | 1 ÷ 3.20 = 0.3125 | 31.25% |
| 5.00 | 1 ÷ 5.00 = 0.2000 | 20.00% |
| 11.00 | 1 ÷ 11.00 = 0.0909 | 9.09% |
Shorter odds imply a higher chance. Longer odds imply a lower one.
Where this stands: every conversion in the table is checkable by hand.
Implied is not the same as true
Take a two-way market priced at 1.90 and 1.90. Each side implies 52.63%. Together they imply 105.26%, which is more than certainty.
The excess is the margin built into the prices. The overround page shows how it is calculated. Because of it, an implied figure overstates the chance of every outcome a little.
Where this stands: implied probabilities across a market add to more than 100%.
Implied probability and your own estimate
Your estimate is your opinion of the chance. It is not a fact, and the market does not owe you agreement.
Compare the two in the expected value calculator. The break-even point for any bet is its implied probability: below it, the bet loses on average; above it, the bet gains on average, if your estimate is right. Are bookmaker odds fair? covers the margin question.
Where this stands: the break-even chance of a bet is its implied probability.
Sources and what is not yet read
| Item | Source to read | Status |
|---|---|---|
| Wording of the definition | A regulator, help service or organiser glossary | Not confirmed on 2026-11-13 |
| Formula and examples | Derived on this page | Calculated 2026-11-13 |
| Decimal odds on operator pages | Operator pages | Not confirmed on 2026-11-13 |
For notation, see how to read decimal odds; for the wider picture, how betting works.
Where this stands: the arithmetic is derived; outside wording is still to be read.
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FAQ
How do you work out implied probability?
Divide 1 by the decimal odds. For odds of 3.20, 1 ÷ 3.20 = 0.3125, which is 31.25%.
Is implied probability the real chance of winning?
No. It is the chance the price suggests. The price includes the bookmaker's margin, so the implied figures for all outcomes add up to more than 100%.
What is the difference between implied probability and my own estimate?
Implied probability comes from the price. Your estimate is your own opinion of the chance. The two are compared in the expected value calculator, and your estimate is not a fact.
Can I convert odds below 1.00?
Decimal odds start above 1.00. The calculator on this site asks for odds of 1.01 or more.