Hi Allan, Michael is spot on, but I wanted to clarify a bit. The percent complete can be based off duration or planned hours, depending on what you have set up in Setup -> Project Preferences. If it's duration, it'll go off the duration of the subtasks. If it's planned hours, it'll go off of when the task is completed, but only if the planned hours are filled out. To take your example and provide depth to it, look at it as follows: Make tea - 2h duration, 2 planned hours Boil kettle - 1.5h duration, 1.5 planned hours Pour hot water in the cup - .5h duration, .5 planned hours, predecessor of Boil kettle Seeing as we have both the duration and planned hours filled out, it would work either way. However, we could set the durations to 0d, and keep the planned hours, and if your settings in Setup are configured off planned hours, it would show 0% until both subtasks are complete. Conversely, if we keep the duration and remove the planned hours, it'll show 75% complete when Boil kettle is completed. To top it off, if the setting in Setup is set to planned hours, it's exactly opposite. I hope this helps! Thanks, Dustin Martin Assigned Support Engineer Workfront