Expected value calculator
Enter possible outcomes and matching probabilities or weights. The calculator normalizes them automatically.
Expected value components
| Row | Outcome x | Weight | p | x · p |
|---|---|---|---|---|
| Fill in the fields above — the result is computed on this page. | ||||
How do I use this page?
- Enter outcomes in the first field.
- Enter matching weights in the same order.
- Review the x·p table and total.
What this page does not do: The result requires a complete, accurate list of outcomes and weights. Unknown probabilities should not be guessed.
Further reading
Theory — what does expected value mean?
Expected value is the average outcome of a random model over very many repetitions, not a promise about any single trial. The calculator lets you enter possible outcomes with matching probabilities or weights, which do not need to sum to one — it divides each weight by their total. Weights must be non-negative and their sum positive, otherwise normalization makes no sense. A negative expected value indicates an average loss over the long run, not a certain loss in one trial.
Frequently asked questions
Must the weights sum to 1?
Is expected value the most likely result?
See also
A/B test calculator
Compare two proportions in an A/B test. Calculate conversion rates, difference, uplift, z score, p value and c
A/B test planning — sample size, MDE and duration
Plan a two-proportion experiment, estimate detectable effect and traffic duration.
ACF and PACF autocorrelation calculator
Calculate ACF and PACF across time-series lags. Review the chart, reference bounds and coefficient table.