WinUI 3 Calculator

January 1, 2026 · View on GitHub

A modern, open-source Windows calculator built with WinUI 3, featuring MVVM architecture, Fluent Design System, and full keyboard support.

Features

🧮 Full Calculator Operations - Addition, subtraction, multiplication, division, percentage
🔢 Advanced Functions - Square root, square, reciprocal, negate
⌨️ Complete Keyboard Support - Use numpad or keyboard for fast input
🎨 Fluent Design - Electric Blue accent with Mica backdrop
🌙 Dark/Light Theme - Follows Windows system theme automatically
♿ Accessible - Full keyboard navigation, screen reader support
📋 Clipboard Integration - Right-click to copy results

Screenshots

Coming soon

Requirements

Windows 10 (1809+) or Windows 11
.NET 9.0 SDK
Windows App SDK

Getting Started

Clone the Repository

git clone https://github.com/YOUR_USERNAME/winui-calculator.git
cd winui-calculator

Build and Run

dotnet build
dotnet run

Run Tests

dotnet test calculator.Tests

Project Structure

calculator/
├── Commands/
│   └── RelayCommand.cs           # ICommand implementation for MVVM
├── Helpers/
│   └── ServiceLocator.cs         # Lightweight dependency injection
├── Services/
│   ├── ICalculatorEngine.cs      # Calculator logic interface
│   └── CalculatorEngine.cs       # Math operations implementation
├── ViewModels/
│   └── CalculatorViewModel.cs    # Main ViewModel with all commands
├── Styles/
│   └── CalculatorStyles.xaml     # Button styles, animations, colors
├── Views/
│   ├── MainPage.xaml             # Calculator UI layout
│   └── MainPage.xaml.cs          # Keyboard handling
├── calculator.Tests/             # Unit tests (xUnit)
├── App.xaml                      # Resource dictionary references
└── App.xaml.cs                   # Window configuration, Mica backdrop

Architecture

This project follows the MVVM (Model-View-ViewModel) pattern:

Model: CalculatorEngine handles all mathematical operations
ViewModel: CalculatorViewModel manages UI state and commands
View: MainPage.xaml defines the calculator UI

┌─────────────┐     ┌──────────────────┐     ┌──────────────────┐
│  MainPage   │────▶│CalculatorViewModel│────▶│ CalculatorEngine │
│   (View)    │     │   (ViewModel)     │     │    (Service)     │
└─────────────┘     └──────────────────┘     └──────────────────┘
      │                      │
      │      x:Bind          │      ICommand
      └──────────────────────┘

Keyboard Shortcuts

Key	Action
`0-9`	Enter digits
`.`	Decimal point
`+`	Add
`-`	Subtract
`*`	Multiply
`/`	Divide
`Enter`	Calculate result
`Backspace`	Delete last digit
`Escape`	Clear all
`Delete`	Clear entry
`Ctrl+C`	Copy result

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Fork the repository
Create your feature branch (git checkout -b feature/AmazingFeature)
Commit your changes (git commit -m 'Add some AmazingFeature')
Push to the branch (git push origin feature/AmazingFeature)
Open a Pull Request

Development Guidelines

Follow MVVM pattern
Add unit tests for new calculator operations
Use Fluent Design guidelines for UI changes
Ensure accessibility (AutomationProperties, keyboard navigation)

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

Built with WinUI 3
Inspired by the Windows Calculator
Icons from Segoe Fluent Icons