When you first create a task, its late finish date is the same as the project finish date, and its late start date is calculated as the project finish date minus the task duration. As you link the task to predecessors and successors and apply any other constraints, application calculates the late start date as the last possible date this task could be started if all predecessor and successor tasks also start and finish on their late start and late finish dates.
Likewise, the late finish date is calculated as the latest possible date this task could finish if all predecessor and successor tasks also start and finish on their late start and late finish dates. If there is a delay on successor tasks, this delay is also figured into the date in the Late Start and Late Finish fields. These calculations are based on a fixed duration.
Add the Late Start field to a task view, along with the Early Start, Early Finish, and Late Finish fields, to analyze any delay and find any available slack time in your schedule.
Note You can quickly see these fields on Gant Chart view. Apply the Scheduling table, then insert other desired columns.
Late finish date: The latest date that a task can finish without delaying the finish of the project. It is based on the task's late start date, as well as the late start and late finish dates of predecessor and successor tasks, and other constraints.