What are Project Milestones and Why are they so Important?

A milestone is a task of zero duration that shows an important achievement in a project. Milestones are a way of knowing how the project is advancing if you are not familiar with the tasks being executed. They have zero duration because they symbolize an achievement, a point of time in a project.

gantt chart milestones

Example – The red markers are milestones in the above timeline picture

For example – You are building a house for your family and all you can think off are milestones: “The floors will be finished on Wednesday”, “The roof will be completed on Dec 15th”, “The gas installation will be connected at the end of the year”. We intuitively talk about milestones, not tasks, because we do not know how to build a house, and our friends ask us about the construction in terms of milestones: “When are you going to finish the roof?”, “When are you going to move in?”, etc.

A best practice in planning a project suggests we place key milestones in the schedule in order to manage stakeholders’ expectations. This practice helps us define a dashboard for all projects, identify the milestones that have been reached and those that are behind, and manage expectations of those that are involved in the project.

Some important milestones are

  • Key Dates  Parties, board meetings, product rollouts and other key dates mark significant pieces of your project.
  • Key Deadlines
  • External Dates and Deliveries For example, a due date for a deliverable you are expecting from a client,  the date when your product has to be delivered, or the day that raw material is scheduled to arrive.  These key events can affect when other tasks in your project are allowed to start.

The best way to display milestones is to use a Gantt Chart.


Do you know that you can quickly create Gantt Charts within Excel and highlight all Milestones? Click here for our free excel template.

Gantt Chart Excel Template Ribbon
Gantt Chart Excel Timeline