WeWorked has a built in task timer to help you keep track of the time you spend on individual tasks. You can start and stop the timer whenever you like. The timer will also add recorded time to the time you previously entered. All the math is done for you automatically.
To use the timer, switch to the daily view screen.
Then click the timer icon beside the task you want the timer to keep track off. You must add the task to the timesheet before you can start using the timer. The timer will start automatically.
Once you finished working on the task, click Add Time to Task. Your changes are automatically saved and the new time is added to any existing time.
You must keep the timer screen window open for the timer to work. Just open another tab in your browser if you need to do other things.