Free statistics calculators for sample size, standard deviation, p-values, confidence intervals and probability — using proper numerical methods, not shortcuts.
Everything from study design to hypothesis testing.
Required sample size for surveys and A/B tests.
Open calculator →Mean, variance and SD for a data set.
Open calculator →P-values from z, t or chi-square statistics.
Open calculator →CIs for means and proportions.
Open calculator →Normal, binomial and Poisson probabilities.
Open calculator →We use real distribution functions (normal, t, chi-square, binomial, Poisson) so your p-values and intervals match statistical software.