Milestone
A milestone is a point in a schedule with no duration that marks an event, such as a sign-off, a delivery or a go-live, rather than a piece of work. Milestones are linked like tasks, so they move when the work before them moves.
Milestones give a plan its checkpoints: they are what sponsors watch and what contracts often name. Because they carry no work, they cannot absorb a delay; whatever reaches them shows.
In a predecessors table a milestone is a task with a duration of zero.
Worked example
| Task | Duration | Depends on | Scheduled | Total float | After the delay |
|---|---|---|---|---|---|
| 1. Cutover rehearsal | 3 days | None | Days 1 to 3 | 0 days | Days 1 to 5 |
| 2. Cutover | 2 days | 1 | Days 4 to 5 | 0 days | Days 6 to 7 |
| 3. Go-live | Milestone | 2 | Day 6 | 0 days | Day 8 |
The delay: Cutover rehearsal takes 2 days longer.
Go-live follows Cutover, so it lands on day 6. If the rehearsal runs 2 days late, the milestone moves with it, to day 8.
Open this example in the free delay simulator to change the durations, the links or the delay and watch the schedule move.