Fair Odds

The average amount a bettor can expect to win or lose per bet if the same bet were placed many times. Formula: EV = (Probability of Winning x Profit) - (Probability of Losing x Stake). A positive EV (+EV) indicates a profitable bet over the long term. EV is the single most important concept in professional betting.

The actual likelihood of an outcome occurring, independent of the bookmaker's margin. True probability cannot be known with certainty, but it can be estimated through statistical models, historical data, and analysis. When your estimated true probability exceeds the implied probability, you have found a value bet.

A mathematical function that describes the likelihood of all possible outcomes in a betting event. Common distributions used in sports betting include the Poisson distribution for goals/points, the normal distribution for point spreads, and the binomial distribution for win/loss sequences. Understanding distributions helps bettors build predictive models.

A bet where the expected return is positive, meaning it will be profitable in the long run if placed repeatedly. A +EV bet occurs when the odds offered are higher than the true probability warrants. For example, getting odds of 3.00 on an outcome with a 40% chance of occurring. Professional bettors exclusively seek +EV opportunities.

A bet where the expected return is negative, meaning it will lose money in the long run if placed repeatedly. Most bets offered by bookmakers are -EV due to the built-in margin. A -EV bet occurs when the odds offered are lower than the true probability warrants. Recreational bettors predominantly place -EV bets.

Traditional odds format used primarily in the UK and Ireland, expressed as a fraction (e.g., 5/2). The first number represents potential profit and the second represents the stake required. So 5/2 means you win $5 for every $2 staked. Fractional odds of 1/1 (evens) are equivalent to decimal odds of 2.00.