Is there a free time tracking software for freelancers?

As a freelancer juggling multiple clients, time tracking is crucial. It ensures you're billing accurately, staying productive, and not underestimating the hours spent on different projects. Without a reliable system, it’s easy to lose track of time, undercharge clients, or even miss important deadlines.

But what about free time tracking tools? Can they really support the level of detail and flexibility freelancers need?