By Team Edtoolkits · Study & learning
Normal, binomial, Poisson and t-distribution probabilities (below, above, between, exactly) and critical values for any tail area, with a shaded chart and the working.
Use the guide alongside the working tool.
Open Probability Distribution Calculator →Get started
Choose the distribution and enter its settings (mean and spread, trials and chance, rate, or degrees of freedom).
Adjust and explore
Choose Probability to find an area, or Critical value to find the cut-off for a tail area such as 0.05.
Save and share
Read the answer, see it shaded on the chart and follow the working.
Privacy and limits
Computed in double precision with standard numerical methods (about 12 correct digits). Discrete cut-offs are whole numbers, so the tail area reached can be a little below what you asked for; the tool shows the exact area. Binomial n is limited to 1,000,000. Nothing you enter leaves your device.
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Try Probability Distribution Calculator →Explore a related workflow
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