Expected value calculator

Calculate E(X) — the long-run average value of a random variable. Enter outcomes and their probabilities.

Outcomes (x)

Probabilities

E(X) = Σ xᵢ × P(xᵢ)

Fair die: E(X) = 1×(1/6) + 2×(1/6) + ... + 6×(1/6) = 21/6 = 3.5.

E(X) is the average outcome over many repeated trials. For a fair die, you'd average 3.5 per roll over thousands of rolls.