Gantt Chart

Gantt chart history, information and resources

Gantt Chart

What is a Gantt chart

A Gantt chart is a type of bar chart that illustrates a series of tasks or activities on a timeline. Each task is a small step that must be finished as part of completing a larger objective. The tasks are arranged in a cascading order on the timeline, based on their start date.

Gantt charts are effective because they break down a body of work into smaller project tasks and they present the whole effort in a visual way on a timeline. Since Gantts show the work’s tasks in a sequence, they make it easy to see what work needs to be done first and which tasks are dependent on others.

Gantt charts are a popular way to track a project’s progress from day one until completion. They are used by business managers and teams to plan projects and properly manage them so deadlines are met.

project Gantt chart

Gantt chart history and evolution

An early form of the Gantt chart was created in 1896 by Karol Adamiecki, a Polish engineer and management researcher. He created a diagram to make production schedules easier to understand. It illustrated how each part of the schedule was dependent on other parts and he called it a harmonograf. Although Adamiecki published articles about the harmongraf in Russian and Polish, they were never published in English and his ideas were little known in the English speaking world.

Fifteen years after Adamiecki created the harmonograf, an American productivity consultant and engineer named Henry Gantt evolved the diagram. Gantt believed that better scheduling was the key to increased productivity. He designed his diagrams so everyone in an organization could read them and understand them. His charts illustrated the start and finish date of each task, how long they should take and whether they were behind of schedule. It was this charting technique that formed the foundation for modern Gantt charts.

Gantt chart software

Originally, all Gantts were drawn by hand. The rise of personal computers helped solve the challenge of how to make a Gantt chart easily and how to update it quickly when project details changed. Gantt chart maker software was developed so teams could manage increasingly complex project schedules more efficiently. With the advent of the internet, online Gantt chart developers were able to introduce the collaborative, real-time, web applications that are commonly used today.

Office Timeline user interface

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Gantt chart use

Although most commonly utilized by planners and project managers in industries like information technology, pharmaceuticals, manufacturing and professional services, Gantt charts are widely used for planning and tracking any type of program or campaign. Since they are graphical, Gantts are frequently used to present plans or review the progress of work. Gantt charts are used widely across many professions including litigation, forensics, event management and academia.

Elements of a Gantt chart

Gantt charts range in complexity. A simple Gantt chart is made up of the following elements:

  • 1A timeline that can be presented in hours, days, weeks, months, quarters or years
  • 2Milestones that show an event or point in time on the timeline
  • 3Tasks bars that have a start date and a finish date for each item
  • 4Percent complete indicators to show how far each task has progressed
  • 5A Today or Time Now line to denote the current date on the timeline

More complicated Gantt charts introduce elements such as task dependency, critical path timelines and task duration variances.

complicated Gantt chart

How to make a Gantt chart

Gantt charts lay out all the tasks of a project, in order and on a timescale. To make a Gantt chart you will need to first build a project schedule. Here are the steps to follow for creating a project schedule. Spreadsheets, Gantt chart templates or free Gantt chart software can be used to simplify the process.

Identify the major project deliverables and dues dates

  1. Break down the deliverables into smaller, logical pieces of work. These smaller pieces of work are referred to as tasks. You may need to break big tasks into even smaller pieces of work called sub-tasks.
  2. In a spreadsheet, create a Gantt table with 4 columns: Description, Start Date, End Date and Duration (Days). See example below
  3. List all tasks and sub-tasks on your Gantt table under the column titled Description. List them in chronological order, starting with the first task that needs to be done and put all remaining tasks in sequence until the final task.
  4. Estimate the duration, or how long each task will take to complete in days, weeks or months and list those estimates in your table under the Duration column.
  5. Determine key milestones that your project must prepare for. List these in the table’s Description column and give each milestone a 1 day duration to signify it is a milestone.
  6. Begin to build out your project schedule by adding a start date and end date for each task and milestone. Begin by determining the start and finish date of your first task and list those in the Start Date and End Date column.
  7. Continue listing the start at end dates for every task on the list. To do this, you will have to consider dependencies since many tasks will not be able to start until a preceding task has been fully completed.
Gantt chart Excel timeline table

Once your project has been broken down into an ordered project schedule, you will need to transform it into a Gantt chart. You can use a Gantt chart maker, free Gantt chart template or online Gantt chart tool to help do this. One common way of creating visuals is to use the charting tools in spreadsheet applications like Microsoft Excel. See How to make a Gantt chart with Excel. If your Gantt is going to be used for communications or presentations, find a Gantt chart creator that works with graphical software like Microsoft PowerPoint. Gantts made with graphical tools are easy to read and visually impressive.

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It was Henry Gantt’s intention to make a chart that illustrated project schedules simply so that everyone in an organization could understand them. Over time, Gantts became increasingly more complex in order to help teams manage massive projects. Although powerful, these Gantt charts became complicated and difficult for non-project audiences to understand.

project management

This lead to the development of a higher-level Gantt chart for communication purposes, called an Executive Gantt chart. Executive Gantt charts are project management visuals that summarize project plans for clients and stakeholders, without losing them in complexity.

Visualizing projects

Gantt charts were a significant breakthrough because they improved business productivity by providing an overview of project workflows on a timescale. But they were revolutionary because they did this visually. Their ability to instantly communicate plans, status and schedules as a visual is the reason Gantt charts are the most widely used tool for planning or managing a project.

Office Timeline is a PowerPoint Gantt chart maker that creates Executive Gantt charts for important communications. Office Timeline Gantts are visual and designed specifically for communicating with stakeholders and non-project audiences. The free tool builds simplified Gantt charts that anyone can read and easily quickly understand. Office Timeline Plus integrates with popular project management and spreadsheet applications like Microsoft Project, Microsoft Excel and others, so users can import existing project data and instantly transform it into an impressive PowerPoint Gantt chart.

Gantt Chart FAQ


A baseline is the cost, schedule and scope of the project as documented and approved in the original plan. During the execution of projects, a baseline is used to determine if current progress is tracking according to the original plan or whether it has deviated.

Critical Path

The critical path is the sequence of tasks on a Gantt chart that control the eventual completion date for the project. If one of the critical tasks is completed 5 days late, then the eventual end date of entire project will also slip by 5 days.


A task duration is the amount of time it takes for project teams to complete one of the tasks on a Gantt chart, measured from the task’s start date to its end date. Estimating the duration of each task helps project managers establish the project timeline and the project’s completion date.


Dependencies refer to the relationship between tasks on a Gantt chart in which certain tasks need to be completed before successive tasks can begin. Dependent tasks are those that cannot begin until a preceding task has been completed.


Some tasks on a Gantt chart can begin later than planned, without delaying the start date of successive tasks. Float refers to the amount of time a task can be put-off without effecting the plan for the remaining tasks (free float) or the project completion date (total float). Float in project management is also referred to as Slack.

Milestone Definition

Milestones are defined as significant progression points on a timeline that need to be reached for the successful delivery of a project. Project managers and other stakeholders use milestones on a timeline to assess whether projects are on schedule or not.

Task Definition

Tasks are the small pieces of work or assignments that project teams need to complete within a defined amount of time. Each task has a specific start date and end date and they are placed in order on a Gantt chart based on which needs to be completed before others can begin. Completion of all tasks means the project has been completed.

Work Breakdown Structure (WBS)

WBS is a structured process that project delivery teams use to break work down into smaller, more manageable pieces called tasks. The process can be continued in a hierarchical way to further break each task into to sub-tasks. Work breakdown structure is used to organize and scope project work.

Project Plan

Project plans are formally approved, written documents that provide guidance for delivering a project and managing it. They help project teams and stakeholders understand the reason and decisions for the project, the scope of the project, its costs and its schedule. Project plans often include a baseline Gantt chart.

Project schedule

A project schedule is a list of all the milestones, tasks and sub tasks in a project and their start dates and due dates. Schedules are produced using the Work Breakdown Structure process and the resulting list is often transformed into Gantts chart. Project schedules are used to communicate the entire effort of a project.


Timelines are graphics that illustrate a sequence of project events or milestones in a chronological order on a time scale. Timeline charts show the progression of events or milestones along a linear scale.