What Is a Gantt Chart?

A Gantt chart is a type of bar chart that illustrates a project’s schedule. Henry Gantt popularized its use in the early twentieth century.

Written by Adam Thomas
Published on Jan. 24, 2023
Gantt chart image of a man's hand on a clear screen drawing out a Gantt chart with his index finger
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A Gantt chart, frequently used in project management, is one of the most common and effective methods of plotting activities (tasks or events) against time. On every Gantt chart you’ll see a list of the activities on the chart’s y-axis and a suitable time scale along the x-axis (either on the top or the bottom). Within the chart you’ll see a horizontal bar that indicates the progress of each activity. The location and length of the bar corresponds to how far along each task is at any given point.

Gantt chart image of a sample Gantt chart with Tasks A, B, C, D running along the y-axis and a timeline running along the x-axis on the bottom. Red bars run across the chart horizontally to indicate how close a particular task is to completion.
Sample of a Gantt chart. | Image: Adam Thomas

What Is a Gantt Chart Used For?

A Gantt chart is a project management tool used to track the progress of work completed over time in relation to the time planned for that work. It’s a horizontal bar chart to help your team organize projects and improve overall project visibility. 

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Key Components of a Gantt Chart

The key components of a Gantt Chart are the following:

  • Projects: What are the overall projects and tasks this chart will track? Good Gantt charts leverage color to help an observer understand how tasks are paired and what kind of dependencies those pieces have to one another. 
  • Time: When does a project start and end? Anyone reading a Gantt chart should have a clear understanding of the expected timeline and where each piece of the project is within that timeline. 
  • Status Bar: Each component of the project has a horizontal status bar that indicates how far along any given task is at a point in time. 
  • Supplemental Information: What else do we need to know about the project? Good Gantt charts will add supplemental information indicating things like whether a task is higher priority than other tasks, who is responsible for each task and contact information for the responsible parties. 
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What Are the Benefits of a Gantt Chart?

  • A Gantt chart helps you see the work timeline for one or multiple teams. This helps us understand where the team’s resources are going and if there need to be any adjustments.
  • A Gantt chart helps a team understand timelines and communicate priorities to other teams. At a glance, a team can see the progress of particular tasks or the entire project and understand dependencies and potential blockages.
  • A Gantt chart helps a team track if something is running late and can guide decisions on what to prioritize.
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What Are the Disadvantages of a Gantt Chart?

  • A Gantt chart flattens the information so it’s important to know that what you are seeing is a representation of time, value or importance. 
  • A Gantt chart doesn’t show a task’s contextual importance. Without care, you run the risk of thinking about teams as equal resources and ruining team chemistry to catch up to other team goals. 
  • A Gantt chart doesn’t drive decision making but only shows idealized results. If teams do not combine a Gantt Chart with context, they can hurt alignment because it’ll become easy for individuals to look at the chart and walk away with their own (potentially misguided) assumptions about the progress of a project or task.

 

Types of Gantt Chart Dependencies

  • Finish to Start (FS): A task must be completed before the next task begins. (You must complete Task A  before you start task B). 
  • Start to Start (SS):  A task must be started before the next task  starts (You must start Task A before you start Task B). 
  • Finish to Finish (FF): A task can only be completed once another task is completed (You can only complete Task A once you complete Task B). 
  • Start to Finish (SF): A task can only be completed once another task starts (You can only complete Task A once you start Task B). 

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How to Make a Gantt Chart

You can create a Gantt chart by simply listing projects with their component tasks, their start and end dates, as well as their dependencies. You can do this on something as simple as an Excel notebook or Google sheet. There are also plenty of tools available to get you started. 

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