Clinical trial statistics, in your browser
ClinStats performs the standard sample-size, power, confidence-interval and hypothesis-test calculations used in clinical trial design and reporting. Every calculation runs locally in your browser — no data leaves your device — and all results are reproducible: identical inputs always give identical outputs.
Sample sizes are always rounded up (ceiling), per regulatory convention. Results are shown to 4 significant figures.
Sample size & power
How many subjects do you need — or how much power do you have?
Confidence intervals & tests
Interval estimation and 2×2-table inference for trial results.
Survival
Event-driven sizing for time-to-event endpoints.
How to read a result
Each calculator shows the formula used, its textbook reference, and the assumptions behind it — alongside the numbers. If an input is invalid you get an explanatory message, never a silent NaN.
These are standard textbook approximations for planning and education. Final trial designs should always be reviewed by a qualified biostatistician and computed with validated software. See the full disclaimer in the footer.