Time Sled is a functional time tracking utility that will allow you to account for the time spent on one or another task. You start it when you begin working and you stop it when you finish working.
The tasks you are working on may be grouped into projects. Using such grouping, you may set an hourly rate (the cost of the work performed for the project per hour) for each project. Time Sled will be calculating the time spent on one or another task (project) as well as the total amount according to the indicated hourly rate.
More info:
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