What is the Difference between Gantt Chart and PERT Chart?

Gantt Chart:

Gantt chart was developed by Henry Gantt. A Gantt chart is a form of the bar chart. The vertical axis lists all the tasks to be performed. The bars are drawn along the y-axis, one for each task. Gantt charts used in software project management are an enhanced version of the standard Gantt charts. In the Gantt charts used for software project management, each bar consists of an unshaded part and a shaded part.

PERT Chart

A PERT chart represents the statistical variations in the project estimates assuming these to be a normal distribution. PERT allows for some randomness in task completion times and therefore provides the capability to determine the probability of achieving project milestones based on the probability of completing each task along the path to that milestone. Each task is annotated with three estimates:

Optimistic (O): The best possible case task completion time.

Most likely estimate (M): Most likely task completion time.

Worst case (W): The worst possible case task completion time.

The optimistic (O) and worst-case (W) estimates represent the extremities of all possible scenarios of task completion. The most likely estimate (M) is the completion time that has the highest probability. The three estimates are used to compute the expected value of the standard deviation.

Gantt Chart vs PERT Chart:

Gantt Chart	PERT Chart
1. It stands for Graphical Depiction of a Project Schedule	1. It stands for Program Evaluation Review Technique.
2. Gantt chart is very useful for small, simple and straightforward projects	2. PERT chart is very useful for large and complex projects.
3. This chart can't display inter-dependency between the tasks.	3. This chart display networks of interdependent tasks.
4. Gantt chart uses a bar chart for displaying project details.	4. PERT chart uses a flow chart for displaying project details.
5. A Gantt chart that shows the start and finish dates of a project.	5. A PERT chart allows managers to evaluate the time and resources to manage a project.