Break-even probability
The break-even probability for decimal odds is 1 divided by the odds. At 2.00 it is 50%; at 2.50 it is 40%.
POSITIVE EV BETTING
Positive EV Betting (+EV): Meaning, Formula and Examples
Positive expected value describes a bet whose price is favourable under a given probability estimate. It is one of the central ideas behind value betting, but +EV does not mean a selection is guaranteed to win.
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What does positive EV mean in betting?
Expected value combines two things: how likely an outcome is believed to be and how much the available odds pay. If the potential return, weighted by the estimated probability, exceeds the amount risked over repeated comparable situations, the bet has positive expected value under that estimate.
This distinction matters because a good bet and a winning bet are not the same thing. A well-priced bet can lose, while a badly priced bet can win. +EV evaluates the quality of the price rather than predicting one result.
A simple +EV example
At odds of 2.00, suppose your estimated probability is 55%. The price requires only 50% to break even, so the estimate indicates a positive edge.
Expected value formula
For a simple decimal-odds bet, expected return can be thought of as estimated probability × decimal odds. A result above 1.00 indicates positive expected value before considering other practical factors.
Why estimates matter
If the estimated probability is inaccurate, the calculated edge can be misleading. +EV is only as reliable as the assumptions and data behind the probability.
Changing odds
A selection can be +EV at one price and no longer +EV after the odds shorten. The available price is therefore a core part of the calculation.
Long-term thinking
Expected value describes an average expectation over many comparable decisions. Variance means actual short-term results can differ substantially.
How Value404 presents +EV opportunities
Value404 compares bookmaker prices with estimated probabilities and presents the relationship as a value percentage. The Value Scanner lets users review potential +EV selections together with their event, market, bookmaker, odds and probability context.
Frequently asked questions
Is +EV the same as a prediction?
No. A prediction estimates the chance of an outcome. Expected value combines that probability estimate with the price being offered.
Can a +EV bet lose?
Yes. Even an accurately identified positive-EV opportunity can lose on any individual event.
Why can value change?
Bookmaker odds and probability estimates can change. When either side of that comparison changes, the calculated value can change too.
Is +EV the same as arbitrage?
No. +EV relies on a probability estimate. Arbitrage relies on compatible prices across all relevant outcomes of a market.
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