Calendars define when work does and does not happen. For a project plan to be accurate, it must take into account working and non-working time. For example:
Which days of the week are weekdays and which are weekends
How many hours a day work happens, and at what times
Holidays and other days no work is planned
Unexpected delays, such as when the weather is bad
Administrators define calendars, and project planners choose a calendar when creating work packages or adding work steps to work packages.
There are multiple calendars at different levels
Administrators can define multiple calendars at the tenant or company level.
Default calendars provide a starting point for projects and work packages
Administrators choose a default calendar at the tenant level.
When a new project is created, it includes a calendar based on the default tenant calendar.
When a new work package is created, it uses the default project calendar.
At both the tenant and project level, administrators can:
Make changes to the default calendar
Set a different calendar as the default
Any calendar can be used for work scheduling
When scheduling work, administrator can choose:
Any calendar at the tenant or project level
Different calendars for a work package and each of its work steps
Changing the calendar changes the project plan
Calendars are used to calculate the duration of work steps and work packages. In turn, those durations are used to calculate the project plan. When a calendar is changed, the duration of work steps or work packages that use it changes. In turn, that impacts the project plan.