Paymo Track is a complete time-tracking solution for your MAC, Windows, or Linux computer. It offers a stopwatch, an automatic tracker, and a Pomodoro timer. The tracked time can be linked to your tasks and registered in your daily timesheet.
It is the best free productivity tool (integrated time management, including automatic tracking and Pomodoro, with basic project management) I ever used! It really helped me -- when I gave it the opportunity. I honestly recommend it!
Excellent time tracker, project management app, invoicing, expense tracker and so many other features. I have been using it for years and it has literally saved hours of my time in things i'd rather not have to do manually. Bonus feature, full Linux support!!!!
I've used another automated tracking app before and this one is so much better. I can see the times where I was actually using work software and files vs when I've left my desk to take a call or attend to a personal matter. With one click I can allocate a billable task to the tracked time or the space between.