UTCMenuClock

UTCMenuClock is a lightweight macOS menubar app that keeps Coordinated Universal Time (UTC) visible at all times. It is handy for operations teams, distributed work, aviation, astronomy, or anyone who needs a reliable UTC reference next to the system clock.

Features

• UTC clock in the menu bar using monospaced digits for stable alignment.
• Toggle 24-hour/12-hour display, seconds, date, Julian day, and timezone suffix.
• ISO-8601 override for the menubar text plus “Copy as ISO-8601.”
• Copy the current UTC timestamp (using your selected format) to the clipboard.
• “Open at Login” toggle built into the menu.

Download prebuilt binary

• Grab the unsigned universal binary: downloads/UTCMenuClock_v1.5_universal.zip.
• Because the app is unsigned, macOS will warn on first launch. Use Right Click > Open to allow it, or permit it under System Settings → Privacy & Security.

Build from source

• Requirements: macOS 15+, Xcode 16 (project is updated for ARC).
• Open UTCMenuClock.xcodeproj, select the UTCMenuClock scheme, then build & run.
• Code signing uses ad-hoc identity (CODE_SIGN_IDENTITY = "-") so the project builds without an Apple Developer certificate. Debug builds disable hardened runtime so XCTest can load; Release builds keep hardened runtime enabled. To ship signed/notarized builds, set CODE_SIGN_IDENTITY to your Developer ID, restore DEVELOPMENT_TEAM, and archive from Xcode.
• App version is controlled by MARKETING_VERSION and CURRENT_PROJECT_VERSION in the Xcode target build settings.
• The built app will appear in Xcode’s derived data when using a Release build.

Create installer or zip

The legacy PackageMaker project has been replaced with Apple’s modern pkgbuild / productbuild tooling under packaging/.

./packaging/build-release.sh

This script:

1. Builds a Release universal UTCMenuClock.app
2. Writes packaging/output/UTCMenuClock_<version>_installer.pkg
3. Writes packaging/output/UTCMenuClock_v<version>_universal.zip

The .pkg installs the app into /Applications (system or user home, depending on where the installer is run). Sign and notarize the package before wide distribution if you use a Developer ID certificate.

Using the app

• Launching the app adds the UTC clock to the menu bar; click it to open the menu.
• Menu items:
  • Copy copies the current UTC string using your chosen format.
  • Copy as ISO-8601 copies an ISO-8601 UTC timestamp.
  • Toggles: 24 HR Time, Show Date, Show Seconds, Show Julian Date, Show Time Zone, Show ISO8601 Instead.
  • Open at Login toggles a login item; Quit exits the app.
• When Show ISO8601 Instead is enabled, the other format toggles are disabled and the menubar displays a full ISO-8601 string.

Troubleshooting

• Unsigned app: allow it via Right Click > Open or Security settings after the first block.
• If the clock stops updating after sleep, toggle a preference or restart the app to rebuild the timer (the app also listens for wake events).

Credits

• Built and maintained by John Adams (jna@retina.net).
• LaunchAtLoginController by Ben Clark-Robinson (ben.clarkrobinson@gmail.com).
• Licensed under the Apache License 2.0. See LICENSE for details.