Date Countdown

Date Countdown is a small Windows countdown app built with WinUI 3. It helps you keep track of important dates with a compact desktop interface, optional startup notifications, Windows 10 Start tile updates, and Windows 11 Widgets integration.

Features

• Multiple Countdowns: Create and switch between multiple saved countdowns.
• Compact Interface: A focused date and title editor designed to stay small and unobtrusive.
• Startup Notifications:
  • Enable notifications per countdown.
  • Receive reminders when Windows starts.
• Windows Integration:
  • Windows 10: update a pinned Start tile.
  • Windows 11: provide a Date Countdown widget for the Widgets board.
• Custom Text Size: Adjust the main countdown text and event title text separately with a live preview.
• Sorting: Sort countdowns by days remaining.
• Localization: Includes English and Simplified Chinese resources.

Command-line automation

The Microsoft Store/MSIX installation exposes datecountdown.exe, so AI tools and scripts can add a countdown without opening the editor:

datecountdown add --title "Submit report" --at "2026-08-01T17:00:00+08:00" --timezone "Asia/Shanghai"

--at accepts an RFC 3339 timestamp and must include Z or an explicit UTC offset. --timezone is optional and accepts either an IANA identifier such as Asia/Shanghai or a Windows identifier such as China Standard Time. Pass --request-id with a 32-digit hexadecimal id to make retries idempotent, add --json for a stable machine-readable response, or run datecountdown --help for the complete usage text.

AI agent skill

skills/date-countdown packages the command line as an Agent Skill — an open standard supported by Claude Code, Claude, and other agents. To install it for Claude Code, copy the folder into your skills directory:

Copy-Item -Recurse skills/date-countdown "$env:USERPROFILE\.claude\skills\date-countdown"

The agent then adds countdowns on request ("count down to my exam on March 3rd") using the same datecountdown command documented above.

Requirements

• Windows 10 version 1809 (Build 17763) or later.
• Windows 11 is required for Widgets integration.
• No separate .NET runtime installation is required for the Microsoft Store/MSIX package.

Building

1. Open the solution in Visual Studio 2022.
2. Ensure the .NET 8 SDK and Windows App SDK workload are installed.
3. Build and run the DateCountdown project.

Screenshots

License

Date Countdown is released under the MIT License.

Acknowledgments

This project was developed with the assistance of AI tools, including GitHub Copilot and Codex, to accelerate development and refine the user interface.