Probability tree calculator
Enter probabilities as values from 0 to 1.
Branch probabilities
Bars show the calculated outcomes.
Calculation branches
| Event | Probability |
|---|---|
| Fill in the fields above — the result is computed on this page. | |
How do I use this page?
- Enter inputs.
- Check the branches and formula.
What this page does not do: The result assumes the supplied conditional probabilities are correct; repeated-trial mode assumes independence.
Further reading
Theory — how does a probability tree work?
A probability tree shows successive events as branches and lets you calculate the probability of an entire path. The calculator applies the multiplication rule for independent events and the complement rule when you need the probability that an outcome does not occur. Every intermediate value is shown on its branch, so you can trace where the final result comes from. Probabilities are entered as numbers between 0 and 1, not as percentages.
Frequently asked questions
Can I enter percentages?
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.