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PowerAndSampleSize is an online power analysis and sample size calculation platform for study design. It turns a workflow that would normally require installing R/Python, looking up functions, writing code, and preparing charts into browser-based forms. According to the site, it has been online since 2012 and has received 1,100+ citations. Its new architecture is built on Django, OpenCPU, and PostgreSQL, and is powered by mature R statistical packages.
The platform offers 668+ calculators, with 24 core calculators available on the free tier. Key capabilities include entering parameters such as sample size, effect size, significance level, and power to generate result summaries; using R expressions such as c() and seq() for vectorized sensitivity analysis; exporting results as CSV, copying tables, and exporting power curves as PNG/SVG. Transparency is a major strength: users can view the underlying R code and methodological notes, which helps with verification. Collaboration mainly relies on unique share URLs, making it suitable for citing in papers, grants, IRB submissions, or regulatory materials. However, we did not see enterprise collaboration features such as team workspaces, role-based permissions, or audit logs.
Pricing is relatively clear: Free is $0; daily passes are Starter $7 and Academic $15; monthly subscriptions are Starter $10, Academic $19, and Pro $29; Founding Member is a limited Pro price lock at $15/month; and there is also a limited-time $79 one-time Lifetime Pro offer. Pro includes unlimited runs, 500 result rows, and a commercial use license. The free version is enough to get started, but the daily run limit, result row cap, and sensitivity analysis restrictions are noticeable.
The advantages are that it requires no installation, is easy to get started with, provides transparent methods, costs less than traditional software such as PASS/nQuery, and can generate shareable, citable results. The drawbacks are that payment methods, SLA, security/compliance certifications, API access, and team permissions are not disclosed; on-premise and enterprise deployments are still listed as coming soon. It is especially suitable for applied researchers, clinical and regulatory professionals, graduate students, research consultants, and users who need to quickly generate a sample size section close to a submission deadline.
The main content does not provide information about mainland China access, payment, or localization, so access status can only be rated as unknown. If access or payment is restricted, alternatives include G*Power, PASS, nQuery, or reproducing the calculations locally with relevant R statistical packages.
⚠ This review is compiled from public sources and does not constitute a purchase recommendation. Verify all facts on the vendor's official site. Verify on powerandsamplesize.com official site.
powerandsamplesize.com is an United States Online Tools provider. TG4G tracks its product information, with monthly pricing from $79.00, an overall rating of 8.0/10, and a China-accessibility score of China direct-connect friendly. Click "Visit Official Site" to reach powerandsamplesize.com directly.