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What Is Expected Value in Betting?

Expected value (EV) is the average result of a bet if you could repeat it forever. Here's what it means and why every good bet is +EV.

Updated 18 August 2026.

Expected value, or EV, is the single most important concept in betting: it's the average amount you'd win or lose per bet if you could place it endlessly. Positive-EV betting is the only path to long-term profit. This guide explains it plainly, building on what is value betting?.

What EV measures

EV combines the probability of each outcome with what you'd win or lose, giving the average result per bet. A positive EV bet makes money on average; a negative EV bet loses on average.

It's why single results tell you nothing — only the long-run average matters.

Why value bets are +EV

A bet is positive-EV precisely when the odds are bigger than the true probability warrants — an overlay. That's the same thing as a value bet, expressed as a number.

The bookmaker's margin makes the average bet negative-EV, which you must overcome.

Calculating EV

Multiply your estimated win probability by the profit if you win, subtract the loss probability times the stake, and you have the EV. Our calculators and implied probability tools make it easy.

You need an honest probability estimate — that's the hard part.

Betting for the long run

Focus on making +EV decisions and ignore short-term results, avoiding outcome bias. Over enough bets, positive EV turns into real profit.

A tipster with a genuine edge is simply a source of +EV bets — judge that over a large sample and their Trust Score.

Frequently asked questions

What is expected value (EV) in betting?

The average amount you'd win or lose per bet if you could place it endlessly, combining the probability of each outcome with the win or loss. Positive-EV bets make money on average; negative-EV bets lose on average.

Why is expected value important?

Because it's the only path to long-term profit — you make money by consistently placing positive-EV bets and ignoring short-term results. The bookmaker's margin makes the average bet negative-EV, which you must overcome with value.

Is a positive-EV bet the same as a value bet?

Yes. A bet is positive-EV precisely when the odds are bigger than the true probability warrants — an overlay — which is exactly what a value bet is, just expressed as an average expected return per bet.

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