22 free calculators for sample size planning — t-tests, ANOVA, chi-square, regression, A/B tests, equivalence, Bayesian, and more. Validated against G*Power 3.1. Built for researchers, grad students, biostatisticians, and product teams.
StatPower Pro is designed for how real research actually works.
Drag a slider and the result updates instantly — no "Calculate" button. See how power, effect size, and sample size interact in real time across all 22 tests.
Sign in once and your saved analyses follow you across browsers, laptops, and labs. Row-level security keeps your data scoped to your account.
Toggle any analysis to public and copy a permalink. Collaborators see your parameters, result, and notes — no sign-in required. One click to fork.
Stop guessing what effect size to expect. Our curated database has typical effect sizes by research field (psychology, clinical, A/B testing) with meta-analytic citations.
Generate branded multi-page PDF reports in FDA IND, NIH R01, or ICH E9 format. Ready for IRB submissions, grant applications, and regulatory filings.
Every calculator comes with a sensitivity analysis grid showing required n across effect sizes and power levels. Download as CSV for supplementary materials.
Every power analysis you'll run for the next ten years, in one place.
G*Power is a great desktop app. StatPower Pro is what you want on the web.
| Feature | G*Power | StatPower Pro |
|---|---|---|
| Free | ✓ | ✓ |
| Works on the web (no install) | — | ✓ |
| Live-reactive calculators | — | ✓ |
| Cloud sync of saved analyses | — | ✓ |
| Shareable read-only links | — | ✓ |
| FDA IND / NIH R01 / ICH E9 templates | — | ✓ |
| Effect-size literature database | — | ✓ |
| Runs on mobile | — | ✓ |
| Validated against reference values | — | ✓ (against G*Power itself) |
Straight answers to what researchers actually ask.
Yes. All 22 calculators are free for academic and personal use. Sign in for free cloud sync. We may offer a Pro tier later for teams and enterprises (FDA-bound pharma, for example), but the core calculators will remain free for researchers and students.
Yes. Every implementation has been cross-checked against G*Power 3.1 reference values (see the G*Power Validation page inside the app). StatPower Pro adds live-reactive sliders, cloud sync, shareable links, and regulatory report templates that G*Power does not provide.
By default, no. All calculations run entirely in your browser with zero data sent to a server. Sign in for optional cloud sync of saved analyses — your data is scoped to your account via Postgres Row-Level Security, and we never read or share it.
Yes. StatPower Pro generates branded multi-page PDF reports with ICH E9 / 21 CFR 312 compliant language, suitable for integration into a Statistical Analysis Plan authored by a qualified biostatistician. Consult a statistician for your full SAP.
StatPower Pro includes a curated Effect Size Literature Lookup with typical effect sizes by research field (psychology, clinical, education, economics, A/B testing, biomedical) and meta-analytic citations. Use these as starting points and justify against your specific literature.
There's a "Cite" button in the app that generates APA and BibTeX citations. Or use the in-app "Full Report" feature to generate a complete PDF with automatic self-citation included.
StatPower Pro is built and maintained by Analytica Data Science Solutions. It replaces an earlier R Shiny app with a modern, responsive, cloud-synced experience designed for the way researchers actually work in 2026.
Launch the app and you're running your first power analysis in under 30 seconds.
StatPower Pro