Quasima Chrono Tracker is a time tracking application for Windows desktop. It lets you keep track of multiple projects and categorize how much time you spent working on each of them.

Features include:

• Unlimited number of projects organized into a hierarchical structure
• Totals calculated across time and projects
• Invoicing support: project rates & “invoiced” marker
• Reliable database foundation and data backups

This is a powerful, sophisticated, feature-rich and highly customizable program that used to be commercial but later switched to a freeware license, even for commercial use.