StatSigCalculator — A/B Test Statistical Significance & Sample Size Calculator

An interactive statistical significance calculator for A/B testing. Instantly determine the minimum sample size required for your experiments—no more guessing.

Live app: https://tewei02.github.io/StatSigCalculator/

Features

• Sample Size Calculation — Compute required sample size based on baseline conversion rate, minimum detectable effect (MDE), significance level (alpha), and statistical power
• Real-Time Results — Parameters update instantly as you adjust sliders
• Interpretation Guide — Plain-language explanation of what the numbers mean for your experiment
• Responsive Design — Works on desktop and mobile
• Installable PWA — Add to home screen and use it offline; the calculator is fully client-side, so no data ever leaves the device

Statistical Parameters

Parameter	Description	Typical Value
Alpha (α)	Type I error rate — probability of false positive	0.05
Power (1-β)	Probability of detecting a true effect	0.80
Baseline Rate	Current conversion rate	e.g. 10%
MDE	Minimum detectable effect (absolute lift)	e.g. 2%

Tech Stack

Layer	Technology
Framework	React 19 + TypeScript
Build	Vite 7
Styling	Tailwind CSS 4
Processing	PostCSS + Autoprefixer
Delivery	GitHub Pages + Service Worker (offline shell)

Quick Start

npm install
npm run dev

Build for production:

npm run build
npm run preview

Deployment

Every push to main triggers .github/workflows/pages.yml, which builds the app with Vite and publishes the dist/ output to GitHub Pages. The Vite base is set to /StatSigCalculator/ to match the repository name; the manifest and service worker use relative paths so they keep working under that sub-path.

Project Structure

StatSigCalculator/
├── src/
│   ├── App.tsx          # Main application logic
│   ├── main.tsx         # Entry point + service worker registration
│   └── index.css        # Global styles
├── public/
│   ├── icons/           # PWA + favicon assets (192/512/apple-touch/32)
│   ├── favicon.svg
│   ├── manifest.json    # Web app manifest
│   └── sw.js            # Offline-first service worker
├── .github/workflows/
│   ├── ci.yml           # Lint + build check
│   └── pages.yml        # Build & deploy to GitHub Pages
├── index.html
├── package.json
├── tsconfig.json
├── vite.config.ts
├── tailwind.config.js
└── postcss.config.js

License

MIT