The Gantt chart is a project management tool that displays a graphical representation of the stages or activities in a project work plan over time. Each task displays as a horizontal bar whose length is proportional to its time for completion.
A Gantt chart is logically broken down into three areas. On the left side of the chart is a column where the task and milestone text descriptions are written. On the right side of the chart is the graphical timeline display corresponding to each task or milestone. A third, optional component may be displayed between the task / milestone text and the graphical display which corresponds to the resource column(s) in the spreadsheet.
The Gantt chart displays a project's task and timeline information using calendar dates. The software then calculates the task duration based on the calendar difference between the two dates and the length of the work week.