The Gantt chart is a graphic tool whose objective is to show the expected dedication time for different tasks or activities over a given total time.

In 1896, Karol Adamiecki developed a new means of graphical representation of interdependent processes that is designed to improve the visibility of production programs. Given the position of each task over time, relationships and interdependencies can be identified. In 1931 a more widely known article was published to describe the diagram by Karol Adamiecki, who called it the harmonogram or harmonograf. Adamiecki, however, published his works in Polish and Russian, languages ​​little known in the English-speaking world. At the time, a similar method had been popularized in the West by Henry Gantt (who had published articles on it in 1910 and 1915). With minor modifications, Adamiecki's chart is now more commonly known in English as the Gantt chart, since it was Henry Laurence Gantt who, between 1910 and 1915, modified and disseminated this type of chart in the West.[2][3]​.

In project management, the Gantt chart shows the origin and end of different minimum work units and groups of tasks (called summary elements in the image) or the dependencies between minimum work units (not shown in the image).

Since their introduction, Gantt charts have become a basic tool in project management of all types, with the purpose of representing the different phases, tasks and activities scheduled as part of a project or to show a timeline in the different activities, making the method more efficient.

Basically, as already mentioned, the diagram is composed of a vertical axis where the activities that constitute the work to be executed are established, and a horizontal axis that shows the duration of each of them on a calendar.

Gantt charts do not show the existing relationships between activities, although a certain order of temporal priorities can be deduced from the position occupied by each activity over time. For this reason, for planning the development of complex projects (more than 25 activities) the use of techniques based on precedence networks such as CPM or PERT diagrams is also required. These networks relate the activities so that the critical path of the project can be visualized (that is, the most complex activity or the one that will require the most time) and allow a time scale to be reflected to facilitate the allocation of resources and the determination of the budget. The Gantt chart, however, is useful for establishing a basic relationship between time and workload.