📊 Sample Size Calculator

A modern, minimal desktop app to calculate the ideal sample size for your research, surveys and studies.

• ✨ Overview
• 🎯 Features
• 🖼️ Screenshots
• 🧮 How It Works
• 🛠️ Tech Stack
• 📋 Requirements
• 🚀 Installation
• ▶️ Usage
• 📦 Build a Standalone Executable
• 🗂️ Project Structure
• 🤝 Contributing
• 📄 License

Sample Size Calculator is a lightweight desktop application built with Python and PyQt6 that helps students, researchers, statisticians and market analysts determine how many individuals they need to survey to obtain statistically reliable results.

Whether you are working with a known population (for example, the 2,500 students of a school) or an unknown or very large population, the app gives you the minimum sample size in a single click, using the classic statistical formulas based on the normal distribution (Z-table).

The interface is designed to be clean, dark and distraction-free, with a mint-green accent palette and full English / Spanish support.

The calculator relies on the standard sample size formulas for proportions.

        N · Z² · p · q
n = ─────────────────────────
     e² · (N − 1) + Z² · p · q

      Z² · p · q
n = ───────────────
          e²

ℹ️ Note: If you leave the confidence level or the success probability empty (or enter an invalid value), the app falls back to the defaults of 99% and 50% respectively.

The project is split into two clear layers:

• 🧠 Backend – SampleSize.py: all statistical logic, independent from the UI.
• 🎨 Frontend – Program.py: the PyQt6 interface, styled with QSS.

• 🐍 Python 3.11 or higher – Download Python
• 📦 pip (included with Python)
• 🖥️ Windows, macOS or Linux

git clone https://github.com/ia-MarvinRios/Sample-Size-Calculator.git
cd Sample-Size-Calculator

python -m venv venv
venv\Scripts\activate

python3 -m venv venv
source venv/bin/activate

pip install PyQt6

python Program.py

1. Select the Finite tab.
2. Enter the population size.
3. Enter the confidence level (%).
4. Enter the success probability (%).
5. Click Calculate (or press Enter).

1. Select the Infinite tab.
2. Enter the confidence level (%).
3. Enter the success probability (%).
4. Click Calculate (or press Enter).

Use the ES | EN switch in the top-right corner of the window.

The result is shown in the large mint-colored card at the bottom of the window.

Want to share the app without requiring Python? Package it with PyInstaller:

pip install pyinstaller
pyinstaller --noconsole --onefile --icon=icon.ico --name "SampleSizeCalculator" Program.py

The executable will be generated inside the dist/ folder.

🪟 On Windows, make sure icon.ico is in the project root. The app loads it at runtime, so when distributing, place it next to the executable or bundle it with --add-data "icon.ico;.".

Sample-Size-Calculator/
├── 📄 Program.py            # PyQt6 user interface
├── 📄 SampleSize.py      # Statistical logic (Z-table + formulas)
├── 🎨 icon.svg           # Vector app icon
├── 🎨 icon.ico           # Windows app icon
├── 📁 docs/              # Screenshots
├── 📄 README.md
├── 📄 LICENSE
└── 📄 .gitignore

Contributions, issues and feature requests are welcome!

1. 🍴 Fork the project
2. 🌿 Create your feature branch: git checkout -b feature/amazing-feature
3. 💾 Commit your changes: git commit -m "Add amazing feature"
4. 📤 Push to the branch: git push origin feature/amazing-feature
5. 🔃 Open a Pull Request

This project is released under the CC0 1.0 Universal license. See the LICENSE file for details.