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microsoft/calculator

📈 Trending★ 30,928C++Audience · developerComplexity · 3/5ActiveLicenseSetup · hard

TLDR

Windows Calculator is the built-in calculator app that ships with every Windows computer, offering standard, scientific, programmer, and date calculation modes plus currency and unit converters.

Mindmap

mindmap
  root((repo))
    What it does
      Standard arithmetic
      Scientific functions
      Programmer mode
      Date calculations
    Features
      Currency converter
      Unit converters
      Infinite precision
      Multiple modes
    Tech stack
      C++ and C#
      XAML markup
      Windows platform
    Use cases
      Study Windows app code
      Contribute bug fixes
      Learn XAML design
      Extend calculator features
    Audience
      Windows developers
      App learners
      Contributors

Things people build with this

USE CASE 1

Study how a production Windows desktop app is structured and built.

USE CASE 2

Contribute bug fixes or new features to the official Windows Calculator.

USE CASE 3

Learn XAML markup language by examining a real-world Windows app implementation.

USE CASE 4

Extend the calculator with custom converters or calculation modes.

Tech stack

C++C#XAMLWindows

Getting it running

Difficulty · hard Time to first run · 1day+

Requires Visual Studio, Windows SDK, and building a native Windows UWP app from source with C++ interop.

Use freely for any purpose including commercial, as long as you keep the copyright notice.

In plain English

Windows Calculator is the built-in calculator app that ships pre-installed with every Windows computer. You have almost certainly seen it before, it is that simple calculation tool accessible from the Start menu. The app goes beyond basic arithmetic. It offers four main modes: a standard mode for everyday addition, subtraction, multiplication, and division; a scientific mode for more advanced operations like trigonometry and exponents; a programmer mode aimed at developers working with binary, hexadecimal, and other number bases; and a date calculation mode that lets you find the difference between two dates or add and subtract days, months, and years from a date. There is also a currency converter that pulls live exchange rates and a set of unit converters covering length, weight, temperature, and more. Basic arithmetic uses infinite precision, meaning results never get rounded incorrectly during computation. Microsoft has made the source code publicly available so developers can study how a production Windows app is built, contribute bug fixes, or experiment with the code themselves. It is written in C++ and C# and uses XAML, which is the same markup language used to build the visual layout of Windows apps.

Copy-paste prompts

Prompt 1
Show me how to set up the Windows Calculator source code locally and build it from scratch.
Prompt 2
What are the main components in the Windows Calculator codebase and how do they interact?
Prompt 3
How do I add a new unit converter to Windows Calculator and submit it as a contribution?
Prompt 4
Explain the XAML files in Windows Calculator and how they define the user interface.
Prompt 5
What does infinite precision arithmetic mean in the context of Windows Calculator, and how is it implemented?
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Generated 2026-05-18 · Model: sonnet-4-6 · Verify against the repo before relying on details.