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.
Determine the long-term profitability (Expected Value) of a trade.
(Your belief that the outcome will win)
Deducted from winning profit. Set 0 for gross EV.
Expected Value Summary:
Market Implied Probability:
Expected Value (EV):
Status:
When to use this calculator
Use the EV calculator to check whether a bet has positive expected value before you place it. Enter the decimal odds and your estimated true probability of winning. If EV is positive, the price offers long-term value.
Pair with Ask Bob backtests to validate whether your estimated probabilities hold up on historical data.
Frequently asked questions
What is expected value (EV) in betting?
How do I estimate true probability?
Does +EV guarantee profit?
Disclaimer: For educational and planning purposes only. Not financial or betting advice. 18+ · BeGambleAware.org