Expected Value (EV) Calculator

Expected Value (EV) is the most important concept in profitable betting. It tells you how much money you can expect to win or lose on a bet, on average, over the long run.

How to Use:

• Market Decimal Odds: The price offered by the bookmaker or exchange (e.g., `2.5`).
• Stake Amount: The amount of money you are betting (e.g., `£10`).
• Your Estimated Probability (%): This is the key. You must enter your *own* assessment of the true win probability. This must be more accurate than the market’s implied probability to find value.

The Calculation

The calculator compares your probability against the market’s probability to find the value.

EV = (Profit if Win × Your Win %) – (Loss if Lose × Your Lose %)

Pro Tip: A **Positive EV** (`+£`) means the bet is profitable long-term. A **Negative EV** (`-£`) means you will lose money over time. You should only ever place bets that you believe have a Positive EV.

[Image of positive vs negative expected value graph over time]