Free, deterministic study-planning tools for clinical researchers. No account, no upload — they run in your browser, and every answer is shown with the rule or formula behind it, so you (or your statistician) can check the arithmetic.
These are the same deterministic engines inside RigorMD’s $10 study design plan — pure rule tables and closed-form formulas, no AI in the loop. The free tools show you one honest number or one recommended test. The full plan turns your study description into the whole scaffold: the analysis plan, the variables and data you need to collect, a clearly stated hypothesis with the power to answer it, and a draft IRB statistical-methods page.