Clockbook is the only 100% free time tracking app for Mac that lets you log hours straight from your desktop. Supports Mac OS 10.12 and higher.
Clockbook is a web-based time tracker and Mac-compatible time tracking software. It’s the only time tracking program that’s truly free, no matter how many projects you have or how big your team is. Clockbook is primarily a browser app, but you can also install it on your Mac OS X as a native desktop app to make time tracking more convenient. You can track how many hours you spend working on tasks from the Mac application, and then run reports, manage projects, and review timesheets in the browser version.
When you start working, start the timer with one click (or keystroke).
You can enter what you worked on and add a project, task, tag, and choose if it's billable.
Clockbook can track what apps and websites you use so you can later create time entries based on time spent in other apps (data is visible only to you).
Desktop app has a lot of handy features that can help you better track time, which you can enable in Preferences:
In the web version, you can manage projects, invite team, review timesheets, and export reports.