Expected Value (EV) Calculator

Calculate the expected value of any bet to identify value betting opportunities.

EV Calculator

Enter the decimal odds, your estimated probability of winning, and optionally your stake to calculate the expected value of your bet.

The decimal odds offered by the bookmaker (must be greater than 1).
Your estimated probability of the outcome occurring (0-100%).
The amount you plan to wager. Defaults to 1 if not specified.
Used only for display. Calculations are currency-agnostic.

Understanding Expected Value in Betting

Expected Value is the cornerstone of profitable betting. It helps you identify bets where the odds offered are better than they should be based on the true probability of an outcome.

How Expected Value is calculated

EV is calculated using the formula: EV = (Probability × Odds - 1) × Stake. The EV percentage removes the stake factor: EV% = (Probability × Odds - 1) × 100. A positive result indicates a value bet.

Why use an EV calculator?

  • It helps you make data-driven betting decisions rather than emotional ones.
  • It identifies value bets that offer long-term profitability.
  • It helps you avoid bets with negative expected value.

Common mistakes when calculating EV

  • Overestimating your probability predictions without proper research.
  • Ignoring bookmaker margins when estimating true probabilities.
  • Expecting short-term results to match long-term EV predictions.

Worked Examples

Identifying a Positive EV Bet

A bookmaker offers odds of 2.50 on a football team to win. Your analysis suggests this team has a 45% probability of winning. Enter odds 2.50, probability 45%, and stake £100. The calculator shows an expected value of +£12.50 per bet (EV% = +12.5%). This means that over many identical bets, you'd expect to profit £12.50 for every £100 staked — a strong positive expected value that makes this bet worth taking long-term.

Spotting a Negative EV Bet

A bookmaker offers odds of 1.80 on a tennis player to win a set. You believe the true probability is 50%. Enter odds 1.80, probability 50%, and stake €50. The calculator shows an expected value of -€5.00 per bet (EV% = -10%). Despite a coin-flip probability, the odds don't compensate enough — you'd lose €5 on average for every €50 staked. This is a bet to avoid regardless of how confident you feel about the outcome.

Comparing Markets for Best Value

You estimate a boxer has a 40% chance of winning. Bookmaker A offers odds of 2.80, while Bookmaker B offers 2.40. For Bookmaker A: EV = (0.40 × 1.80) - (0.60 × 1.00) = +12%, a profitable bet. For Bookmaker B: EV = (0.40 × 1.40) - (0.60 × 1.00) = -4%, a losing proposition. Same event, same probability estimate, but one is +EV and the other is -EV. Always compare odds across bookmakers before placing your bet.

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Frequently Asked Questions

A value bet is a bet where the probability of an outcome is greater than what the odds imply. This means the bookmaker has underestimated the likelihood of the outcome, creating a positive expected value opportunity.

Accurate probability estimation requires research, statistical analysis, and experience. Consider team form, head-to-head records, injuries, weather conditions, and other relevant factors. Compare your estimates with implied probabilities from multiple bookmakers.

Yes, in the short term. Positive EV only guarantees profitability over a large sample size. Individual bets can still lose, and losing streaks are normal. The key is to make many positive EV bets over time.