
The below is only applicable with enabled date rollup. To learn more: https://help.easyprojects.net/hc/en-us/articles/7385235334157-Date-Rollup

On activity start and end date, see: https://help.easyprojects.net/hc/en-us/articles/115001822171.
Should you specify no start date, end date, completion rate (progress), or estimated hours for a project, Easy Projects will do it all for you. Below is a description of the way the program will do the calculation and how this will affect associated items, such as activities that belong to the project in question.
If a project has one or more activities, calculating its start and end dates, progress and estimated hours is governed by the following rules:
Parameter | Calculation Rule | Notes |
Start Date |
|
|
End Date |
|
Only top level activities, that is, ones that are not sub- to any activity, are taken into account in the calculations. |
Progress | The project’s progress is calculated as a weighted mean of its activities’ completion rates, or ![]() |
Only top level activities are taken into account in the calculations. |
Estimated Hours | These are calculated as a total of estimated hours of all top level activities the project has plus its own estimated hours. | Only top level activities are taken into account in the calculations. |
Changing project start date
- In Activity Center, locate the project you want to edit.
- Click the project start/end date button (
).
- In the start/end date selector, select proper start date.
- Click 'Save' to save the changes

If a project’s start date is changed, the start dates of all its activities are recalculated automatically, too, with their durations remaining unchanged. The logic that a project can be no shorter or earlier than the earliest and latest task is standard amongst project management tools.
For info on how this is handled by MS Project - see their help page on project start / end dates

Project dates CANNOT be changed manually if it has one or more closed activities whose start or end date determines that of the project. In such a case if you want to change project dates manually you will have to change the earliest start and/or latest end dates of the closed activities first so that project start and end dates are changed accordingly.

A project had July 01, 2006 as its start date, and had an activity starting on July 10, 2006. Then the project’s start date was rescheduled to July 20, 2006. As a result the activity’s start date would be recalculated 19 days forward to become July 29, 2006. The activity’s end date, if specified, would move forward the same number of days.

A project has 250 as estimated hours and it has 2 tasks with 55 and 67 as their estimated hours, respectively.
As a result, the total estimated hours will be shown (Est. Hours column) as 372 (250+55+67).
As a result, the total estimated hours will be shown (Est. Hours column) as 372 (250+55+67).

Project's estimated hours are given in the 'Estimated hours for this project' field. Project's activities's total estimated hours are given in the 'Estimated hours for all activities' field. See Project details screen.