What are Milestones?

In project portfolio management, a milestone marks an important point in a project’s progress that requires monitoring or decision-making. Milestones indicate project phases, marking the completion of objectives or the achievement of a planned action.

Definition | Examples | Synonyms

A milestone is a specific point in the timeline of a project that marks when the project team has reached a significant step toward the project’s ultimate completion.

It serves not only as a reminder that you and your team have accomplished a large portion of the work but can also help track dependencies, manage expectations and guide resource management. Milestones help you perform temperature checks on your projects, allowing you to monitor progress and adjust planning as needed. It’s not about setting a hard deadline for each phase, but rather about using checkpoints to create structure.

Generally, milestones can be events where a component is completed, a new phase begins or decisions need to be made before proceeding. Milestones are usually placed at the end of project phases, though there may also be additional checkpoints within phases. Milestones are always a discrete point in time, never an interval of time.

Hi-fi Screenshot of the Roadmap View with Milestones and Dependencies

A Practical Example

The placement and purpose of milestones depend on your company and the particular kind of project you are working on. Using software or product development as an example, you might your project(s) up with the following milestones:

  1. Project kickoff: This milestone marks the beginning of the project. Goals, resources and the project schedule are determined at this stage.
  2. Definition of requirements: The definition of project requirements typically marks a significant milestone; this helps to shape stakeholders’ needs and expectations.
  3. Completion of design phase: At this stage, technical details and architecture are finalized.
  4. Development completed: After functionality for a software or product has been developed and reviewed, this milestone is reached.
  5. Testing phase completed: After successful testing and quality assurance is completed, you’ve reached the testing phase milestone.
  6. Customer delivery: Once you’ve tested the product, it’s time to deliver it to the client. Delivering the finished product usually marks the second-to-last checkpoint.
  7. Project closure: This milestone marks the end of the project. Document results and feedback and close the project officially.
Finish Line Project Intake

Synonyms and Abbreviations

Milestones can also be referred to as checkpoints. We are not aware of any abbreviations.


Why are milestones important?

They provide structure and guide the way to project completion. At these important points, decisions are also made about whether and how the project will continue. Decision points are particularly important at the conclusion of project phases. It may make sense to set a milestone if you are asking yourself the following questions at the end of a project phase:

  • Do we need to adjust the plan?
  • Would it make more sense to pursue an alternative route?
  • Will I get the ok for the next phase? 
  • Does it make sense to continue with the project?

Milestones ensure a level of quality control. Of course, all the phases and activities of a project could simply be completed one after the other. Still, it is much more sensible to check whether the results achieved correspond with the requirements. Plus, checking milestones can be a motivational factor: Who wouldn’t be happy to achieve an interim result by the planned deadline?

What happens if a milestone isn’t reached in time?

Delays in the project

If you do not reach an important milestone, you have to push it back. This can lead to delays in the entire project, as you can’t yet initiate the later phases.

Resource issues

If you fail to reach a milestone, this can lead to resource constraints caused by delays because resources have likely been allocated to another task for that time.

Budget overruns

If you do not reach a milestone, additional costs may arise. This can be caused by overtime, additional resources or changes in the project plan.

Quality issues

If you fail to reach a milestone, it can affect the quality of the project outcome. If you do not meet key checkpoints, errors or deficiencies may occur.

Decision-making requirements

If a milestone is unachievable, you need to make some decisions. The project team needs to consider how to proceed. Should the project be adjusted, replanned or stopped altogether?

How do you determine where to place milestones in your project plan?

Milestones are important control and decision points in a project. Unlike other elements of a timeline, milestones do not require time to accomplish them. Rather, they mark specific points along the project timeline and serve as guideposts to keep track of a project’s progress.

Milestones are usually determined as follows:

  1. Create a project structure plan: Start by creating a project structure plan that includes all work packages and tasks of the project. This serves as the basis for defining the milestones.
  2. Define milestones: Next, define the relevant milestones. These should mark important control and decision points in the project. For example, project start, requirement definition, completion of the design phase, completion of development, completion of testing phase and project closure.

How are milestones represented visually?

How milestones are visualized depends a bit on the context and what software you might be using. Common formats include:

  • Gantt chart: In a Gantt chart, milestones are displayed as vertical lines or diamonds. They mark the beginning or end of a project phase and help visually track project progress.
  • Work Breakdown Structure (WBS): In the WBS, milestones are listed as specific tasks or work packages. They are clearly defined and have no duration. The WBS shows the hierarchy of tasks in the project.
  • Project timeline: Here, milestones are listed as important dates or events. They are often highlighted in color and can be linked to specific goals or outcomes.

Milestones in Meisterplan

In Meisterplan’s Portfolio Designer, milestones play a central role. Represented as diamonds on each project bar, decision-makers can see at a glance how well a project is progressing.

A special bonus: the milestones are interactive and can be linked to each other. Is Project B dependent on the completion of Project A? In Meisterplan, it’s easy to visually represent this connection. If Project A is a bit behind and you need to change your plan now, you’ll see immediately the potential effect this has on Project B. It couldn’t be easier.

Portfolio Designer with Milestone Dependencies
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