Using Work Calendars in Gantt

Gantt respects work calendars when you are scheduling project tasks. You can create work calendars for each of your organizational entities that have different working days and hours, and different non-working days, such as weekends and holidays. This enables you to have greater control when scheduling your tasks. See the related help topics for more information.

Note: In this release:

All non-working days are colored gray in the Gantt chart.
If you use high volumes of work calendars, Gantt is likely to be slow to load.
The standard hours per day is calculated as the median of the availability hours of all days in the week. We recommend that you use a work calendar with a standard pattern of daily hours.

In Gantt, the Work Calendar field contains the following:

If a project has an associated work calendar, this is used and shown in the field.
If the project does not have an associated work calendar, the 24/7 calendar is used and shown in the field.
For tasks, you can also select a different work calendar from the drop-down list in the field. The list displays up to 500 work calendars, but you can start to type in the field to find the work calendar you want.

Non-Working Days

In a work calendar, a day is classed as a non-working day when:

The day has zero (0) hours.
The start and end time are the same.
A start or end time is missing, which makes the day invalid. You cannot schedule time for an invalid day, even if you have allowed tasks to start or end on non-working days.

Note: When replicating a sequence of task start and end dates for work calendars that respect non-working days, tasks that end on a non-working day are changed to zero hours checkpoints Closed

A zero duration task record, which is used to represent an event in the project such as a key decision, completion of a work package, completion of a deliverable or end of a phase. Checkpoint tasks have no relationship with PSA milestones.. Also, if you are replicating a sequence using only the end date, tasks can end on non-working days.
Use only start dates to replicate a sequence of tasks and ensure that the task end dates will not fall on a non-working day.

Changing Work Calendars

Work calendars for existing project tasks do not change if you add or change a project's work calendar, but new tasks use the project's new work calendar.

If you select the 24/7 work calendar for a task instead of another calendar, the task starts at the same time as the original calendar and runs for 24 hours. For example, if the original task was 0800 - 1700 on 25 July, selecting the 24/7 calendar changes this to 0800 on 25 July - 0800 on 26 July, with a duration of one day.

You cannot copy and paste a work calendar between project tasks, but you can use the replication handle.

Standard Work Calendars

The 24/7 work calendar is unrestricted to times or days, including weekends and holidays. The standard work calendar in Project Task Gantt (PTG) uses standard 0800-1700 hour days, Monday to Friday.

If you are editing a project in Gantt that was set up using the PTG standard calendar, we recommend that you create and select a work calendar for the project that matches the standard PTG calendar.