Free Statistics Calculators
Free online statistics tools that run entirely in your browser — nothing is uploaded, nothing is stored. Each one is built on the same numerical engine we use in client work and verified against R. Pick a calculator to get started.
Calculators
Choose a tool
Sample size & power calculator
How many participants do you need? Sample size and statistical power for t-tests, two proportions and correlations.
p-value calculator
Convert a t, z or chi-square test statistic into a one- or two-tailed p-value.
Confidence interval calculator
Confidence intervals for a mean or a proportion (Wald and Wilson).
Descriptive statistics calculator
Paste your data and get mean, SD, median, quartiles, range and more.
Correlation calculator
Pearson correlation, r², significance and a scatter plot from paired data.
Which statistical test should I use?
Answer a few questions and get the right test — with the R function to run it.
These calculators are free and always will be. When your analysis outgrows a calculator — real data, assumptions to check, a report to write — that’s what we do.