Redmond Calculator

July 25, 2026

Redmond Calculator is a version of the Windows calculator built with Avalonia and .NET. It is one of the first two applications in the Port Redmond project, together with Redmond Notepad. The calculation engine is the open-source code of Microsoft's Windows Calculator, included unmodified, and Redmond Calculator adds an interface modeled on the original.

Features

The current version has:

  • Calculator modes
    • Standard, scientific, programmer, graphing and date calculation.
  • Converters
    • Volume, length, weight, temperature, energy, area, speed, time, power, data, pressure and angle, plus currency.
  • History and memory
    • A history pane and a memory panel.
  • Currency rates
    • Four sources to choose from: the European Central Bank, the Federal Reserve H.10 tables, the Bank of Canada and Frankfurter. The app only contacts a source after you agree to it in Settings.
  • Appearance
    • A light, dark or system theme and a choice of font. On macOS the window corners and window buttons can follow either Windows or macOS styles.

Keyboard shortcuts

The shortcut list comes from the Windows Calculator's own definitions, including the mode switches and memory keys. On macOS the Ctrl key becomes ⌘. A few shortcuts that would clash with macOS, such as history, memory store and memory subtract, use a Shift or Alt variant on every system. In Settings you can switch ⌘ back to Ctrl. Key names follow your keyboard language, so a German layout shows Strg.

Availability

No release has been published yet. The source code is on GitHub under the MIT licence, and the README has build steps for macOS and Windows. It also runs on Linux.

Frequently Asked Questions

Which modes does it have?
Standard, scientific, programmer, graphing and date calculation, plus unit converters for volume, length, weight, temperature, energy, area, speed, time, power, data, pressure and angle, and a currency converter.
Do the keyboard shortcuts match Windows?
Mostly. The shortcut list comes from the Windows Calculator's own definitions. On macOS the Ctrl key becomes Command, and a few shortcuts that clash with macOS (such as history, memory store and subtract) use a Shift or Alt variant on every system. In Settings you can switch Command back to Ctrl.
Does it need an account or an internet connection?
There are no accounts and calculations run locally. The only network use is currency rates. Each rate source stays off until you agree to it in Settings, and only the latest rate table is requested. The amounts and currencies you enter are not sent.
Where does the calculation engine come from?
From Microsoft's open-source Windows Calculator, which is included unmodified as a pinned Git submodule and used under its MIT licence. Redmond Calculator adds the Avalonia interface and the code that connects the two.
Can I download it?
Not yet. No release has been published. The source code is on GitHub under the MIT licence and can be built with the steps in its README.