Gantt Chart

Also Known As
Activity Chart
Milestones Chart
Project Bar Chart

A Gantt chart is used to outline the plan for and show the progress of a project. It has the format of a bar chart and depicts the various subdivided phases or tasks that must be completed for a project to be finished, and when in the project timeline the phases or tasks need to occur. It is shaded to show progress on which tasks have been completed. It can also show the teams or individuals responsible for completing each task. It allows a project team to make realistic timelines and set realistic goals and expectations for the project, and to focus their attention on the aspects of the project which are most crucial. Because it demonstrates tasks on the project timeline, the chart is very useful for monitoring the progress of a project.


To aid in understanding how tasks or phases of a project overlap and the order in which they need to occur.

To identify critical tasks or phases of a project.

To evaluate a project's progress and deadlines if the project is lagging behind its schedule.

For project scheduling.

How do I use this tool?

1. IDENTIFY THE TASKS that comprise the project and identify primary milestones. There are a number of methods for accomplishing this, including brainstorming, constructing a flowchart or storyboard, or creating an arrow diagram. Determine how much time should be required to complete each task, then determine the sequence the tasks must follow, including which tasks must be completed before the next can start, and which tasks can overlap or occur simultaneously. Identify the task that needs to be finished before reaching each milestone in the project.

2. DRAW A HORIZONTAL TIME AXIS at the top or bottom of a page. Mark it with an appropriate time scale for the length of the project and its tasks (days or weeks).

3. WRITE EACH TASK AND MILESTONE of the project, in order, vertically along the left side of the page. If there is an event that needs to happen at a specific date and time, draw a diamond (solely its outline) beneath the time of the event. If an activity occurs over a period of time, denote this by drawing an unfilled bar under the corresponding times on the timeline, where the beginning of the activity starts at the leftmost point of the bar and ends at the rightmost point.


5. As events and activities occur and are completed, denote their completion by FILLING IN THE DIAMONDS AND BARS on the chart. If tasks are currently in progress, estimate their percentage of completion and fill in that amount of the bar.

6. PLACE A VERTICAL MARKER to denote the current time on the timeline. This can be accomplished with something as simple as a string and two thumbtacks.

Expertise Required
Users of this tool usually have some training or experience in its use.

Provides visual representation of start times, durations, and overlap of tasks within a project.

Is not difficult to create, interpret, or monitor.

Facilitates resource allocation for the project.

Enables a project team to create realistic expectations and attainable timetables.


Offers little room for uncertainty.

Where can I go to learn more?

Tague N. The tools. In: O'Mara P, editor. The quality toolbox. 2nd ed. Milwaukee, WI: ASQ Quality Press; 2005. p. 93-521.

Bauer J, Duffy G, Westcott R. Improvement tools. The quality improvement handbook. 2nd ed. Milwaukee, WI: ASQ Quality Press; 2006. p. 109-48.