Implied Probability & Odds Conversion Table

Implied Probability Calculator & Odds Conversion Table

In this article we explain all you need to know about Implies Probability including how to calculate it manually, a table with some examples and we’ve even created a savvy tool that will automatically do the math for you.

What Is Implied Probability?

Implied Probability is used primarily for sports betting markets and is a conversion of traditional odds into a percentage. The odds of a particular bet correlate to the chance of it happening. However, it also takes into account the ‘house edge‘ and eliminates it to express the ‘true odds‘ of an event occurring.

For example, a bet with fractional odds of 3/1 converts to decimal odds of 4.0 which has an implied probability of 25%. This percentage means the bet is expected to win one in every four attempts. If you believe that the bet should be winning one if every three attempts (which would imply odds of 2/1) then the odds of 3/1 represents value. Furthermore, by backing more ‘value bets’, you also have a better chance of increasing your Return On Investment.

Implied Probability & Odds Conversion Calculator

If you’re looking for a quick calculation, then our Implied Probability and Odds Conversion Calculator is the perfect tool. Just enter the odds in either fractional or decimal format and the rest will automatically be calculated for you.

Fraction Decimal Implied

Alternatively, we’ve created a table below that displays some of the most popular odds in both fractional and decimal form along with the implied probability.

Fraction Decimal Implied Probability
1/5 1.20 83.3%
1/4 1.25 80%
1/2 1.50 66.7%
3/4 1.75 57.1%
1/1 2.00 50%
6/4 2.50 40%
2/1 3.00 33.3%
3/1 4.00 25%
5/1 6.00 16.7%
10/1 11.00 9.1%
20/1 21.00 4.8%
50/1 51.00 2%
100/1 101.00 1%
500/1 501.00 0.2%
1000/1 1001.00 0.1%

How To Manually Calculate Implied Probability

You can also manually calculate implied probability from both fractional and decimal odds.

Fractional Odds

Fractions quote the potential profit should the bet succeed, relative to the stake. For example, if £10 is bet at odds of 2/1 then the potential profit is £20 (2 * £10) and the total returned is £30 (£20 plus the initial £10 stake).

Calculation: Implied Probability = Denominator / (Denominator + Numerator)

Example: 2 / 1 = 1 / (1 + 2) = 1 / 3 = 0.333 = 33.3%

Decimal Odds

Decimals quote the potential return should the bet succeed, relative to the stake. For example, if £10 is bet at odds of 3.0 then the total returned is £30 (3 * £10) and the potential profit is £20 (3 * £10 minus the £10 stake).

Calculation: Implied Probability = 1 / Decimal Odds

Example: 1 / 1.5 = 0.666 = 66.6%


To conclude, implied probability can be very useful, particularly within sports betting markets. Working out the chance of a particular bet happening based on the odds is important and can help with your decision making of whether or not a particular bet offers value. For more explanations of betting terms take a look at our Betting Glossary.