Expected Value (EV)

What is Expected Value?

Expected value is the average result of a bet if it were repeated a very large number of times, stated as an amount per bet.

Why it matters

Expected value is the single figure that says whether a bet gains or loses money over time, independent of the result of any one round.

Example

A 10 euro bet at decimal odds of 2.00 on an outcome with a true 45 percent chance returns 20 euro 45 percent of the time and nothing 55 percent of the time. The expected value is minus 1 euro per bet.

Common misunderstandings

• A negative expected value bet can still win, and a positive expected value bet can lose for a long time. Expected value describes the average, not the next result.

Frequently asked questions

How do I calculate expected value?

Multiply each outcome by its probability, add the results, then subtract the stake.

Can casino games have positive expected value?

Standard casino games are built with a house edge, so expected value is negative. Bonuses with soft terms are the usual exception.

Related terms

• Probability
• Odds
• House Edge
• Margin