Tie Tracker is a free and open source time tracking application. Its usage is meant to be simple and has the goal to lets you track work hours across projects.
Track your productivity and billable hours.
* Simple work hours tracking
* Assign time to clients and projects
* Mark entries as billed
Yet not complicated but effective reporting.
* Weekly work summary
* Daily list of activities
* Export open invoices to XLSX timesheets for Excel, LibreOffice, Numbers, etc.