What is a Gantt chart?

A Gantt chart is a popular solution for visualising a project plan over time, showing what work is scheduled to be completed, when, and by whom.

Used correctly, a Gantt chart provides an at-a-glance update on the status of the project and what remains to be done before completion. This includes information related to project subtasks, beginning and ending dates for each task, estimated time-demands for each task, teams and team members responsible for completing each task, the dependency relationships between tasks and how they support the overall project, timelines for meetings and approvals, and a general overview of the project schedule from beginning to end.

Simply put, a Gantt chart is designed to communicate exactly what needs to be done to ensure successful project completion by an established deadline. As such, it is widely used within project management to coordinate teams and resources towards strategic objectives.

The modern Gantt chart was already well established throughout industries as early as the 1990s, but its origins can be traced back much further to the late 19th century. In 1896, Polish engineer Karol Adamiecki created the “harmonogram,” the earliest known version of what would later come to be known as the Gantt chart. Concurrently, American mechanical engineer Henry Gantt was developing similar ideas on how to organise tasks within production industries.

In 1923, consulting engineer Henry Wallace Clark described the structure, usage, and benefits of Gantt’s work in his book The Gantt Chart; a Working Tool of Management, coining the term Gantt Chart and establishing it within the modern management lexicon. And while the first Gantt charts were hand drawn, making them poorly suited to the growing complexities of advancing manufacturing processes of the 1950s, the eventual introduction of computing software brought Gantt charts back into serviceability.

Today, Gantt charts are among the most commonly used planning and charting techniques in the world.

The right IT framework begets effective collaboration and oversight. As such, many organisations find themselves championing either ITSM/ITIL or DevOps. But committing completely to one approach or the other can be problematic.

ITSM/ITIL and DevOps are not mutually exclusive; each have their own goals and functions. Here, we provide high-level definitions of each, as well as a look into how they relate to one another:

Planning comprehensive projects

Gantt charts allow all involved to visualise the complete scope of the project, including project length, order of tasks, responsibilities, and necessary resources. This greatly simplifies the planning stages that go into preparing for projects, and offers a comprehensive, big-picture view of the work that will go into it.
Graphic of Gantt chart uses

Organising larger projects for proper execution

Large projects with multiple deliverables and incorporating entire teams or departments can become unwieldy and difficult to manage. Gantt charts allow managers to break large projects down into smaller, more-manageable tasks, facilitating effective execution of even the most-complex initiatives.

Facilitating team collaboration between tasks

Guiding complex projects from conception through to completion requires that team members communicate and collaborate effectively. A Gantt chart provides transparency for team members, clearly detailing what tasks remain and who is assigned to complete them. With a clear view of current objectives, next steps, task dependencies, and any delays or other issues that may be slowing the project, teams can coordinate their efforts without accidentally neglecting important steps or doing redundant work.

Estimating workloads and timelines

Given the many different variables associated with project management, it can be difficult to accurately determine how much effort and time will be needed. Gantt charts are an effective approach to workload and timeline estimation, establishing reliable projections that can be used to schedule due dates, create budgets, and allocate resources.

To the uninitiated, a Gantt chart may look intimidating. But the reality is that Gantt charts are designed for ease of use. With a little direction, anyone can become proficient in reading Gantt charts at a glance. This involves recognising the various elements of the chart, and understanding how they work together to provide an accurate accounting of the project status and next steps.

Key elements of a Gantt chart include the following:

Task list

The task list is located vertically along the left side of the diagram. It describes each task within the project, breaking larger tasks down into subtasks. These tasks may also be grouped by department or production stage.


The timeline runs horizontally along the top of the diagram, and details the estimated duration of the project. This can be broken into days, weeks, months, or more. The timeline will include the planned start and end dates for the project, as well as start dates for individual tasks and sub tasks.


Major events, such as approvals, decisions, deliverables, etc., are highlighted within the chart, helping teams focus on important dates and objectives.


Often, essential tasks will depend on the completion of previous tasks. These dependencies are identified within the Gantt chart and represented by lines connecting dependent tasks.

Lag time/lead time

Lag time and lead time are two elements of a Gannt chart that detail the amount of time between tasks. Lag time describes the time between the end of a predecessor task and the beginning of a successor task. Lead time is the amount of time that predecessor task is allowed to start before it otherwise would.

Critical Path

Critical Path is the longest sequence of tasks that must be completed on time in order for the project to complete by its due date.


The resources section refers to the individual or team assigned to complete specific tasks. The resources field may also include equipment resources, as well as consumable resources such as supplies.

Applying advanced IT management technology and built on the award-winning Now Platform, ServiceNow ITBM solutions provide the tools and resources for organisations to direct projects to achieve unmatched business value. Central to this is ServiceNow’s ITBM Gantt chart functionality that is available in the Planning Console.

ServiceNow optimises traditional Gantt charts. Incorporating colour coding, these Gantt charts easily and transparently detail the status of individual tasks and what percentage is already complete. Icons appearing next to tasks show what phase each item belongs to with a toggle switch shows/hides the critical path. Options to add and delete tasks, change dates and dependencies, and accurately access project progress are also included.

Take your Gantt charts further, and experience the advantages of ServiceNow ITBM.

Graphic showing ServiceNow’s ITBM Gantt Chart functionality in the Planning Console

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