> A Gantt chart is a type of bar chart, first developed by Karol Adamiecki in 1896, and independently by Henry Gantt in the 1910s, that illustrates a project schedule and the amount of time it would take for any one project to finish. Gantt charts illustrate number of days between the start and finish dates of the terminal elements and summary elements of a project.
## A note to users
Gantt Charts will record each scheduled task as one continuous bar that extends from the left to the right. The x axis represents time and the y records the different tasks and the order in which they are to be completed.
It is important to remember that when a date, day, or collection of dates specific to a task are "excluded", the Gantt Chart will accommodate those changes by extending an equal number of days, towards the right, not by creating a gap inside the task.
As shown here 
However, if the excluded dates are between two tasks that are set to start consecutively, the excluded dates will be skipped graphically and left blank, and the following task will begin after the end of the excluded dates.
As shown here 
A Gantt chart is useful for tracking the amount of time it would take before a project is finished, but it can also be used to graphically represent "non-working days", with a few tweaks.
Mermaid can render Gantt diagrams as SVG, PNG or a MarkDown link that can be pasted into docs.
```mermaid-example
gantt
title A Gantt Diagram
dateFormat YYYY-MM-DD
section Section
A task :a1, 2014-01-01, 30d
Another task :after a1 , 20d
section Another
Task in sec :2014-01-12 , 12d
another task : 24d
```
```mermaid
gantt
title A Gantt Diagram
dateFormat YYYY-MM-DD
section Section
A task :a1, 2014-01-01, 30d
Another task :after a1 , 20d
section Another
Task in sec :2014-01-12 , 12d
another task : 24d
```
## Syntax
```mermaid-example
gantt
dateFormat YYYY-MM-DD
title Adding GANTT diagram functionality to mermaid
excludes weekends
%% (`excludes` accepts specific dates in YYYY-MM-DD format, days of the week ("sunday") or "weekends", but not the word "weekdays".)
section A section
Completed task :done, des1, 2014-01-06,2014-01-08
Active task :active, des2, 2014-01-09, 3d
Future task : des3, after des2, 5d
Future task2 : des4, after des3, 5d
section Critical tasks
Completed task in the critical line :crit, done, 2014-01-06,24h
Implement parser and jison :crit, done, after des1, 2d
Create tests for parser :crit, active, 3d
Future task in critical line :crit, 5d
Create tests for renderer :2d
Add to mermaid :1d
Functionality added :milestone, 2014-01-25, 0d
section Documentation
Describe gantt syntax :active, a1, after des1, 3d
Add gantt diagram to demo page :after a1 , 20h
Add another diagram to demo page :doc1, after a1 , 48h
section Last section
Describe gantt syntax :after doc1, 3d
Add gantt diagram to demo page :20h
Add another diagram to demo page :48h
```
```mermaid
gantt
dateFormat YYYY-MM-DD
title Adding GANTT diagram functionality to mermaid
excludes weekends
%% (`excludes` accepts specific dates in YYYY-MM-DD format, days of the week ("sunday") or "weekends", but not the word "weekdays".)
section A section
Completed task :done, des1, 2014-01-06,2014-01-08
Active task :active, des2, 2014-01-09, 3d
Future task : des3, after des2, 5d
Future task2 : des4, after des3, 5d
section Critical tasks
Completed task in the critical line :crit, done, 2014-01-06,24h
Implement parser and jison :crit, done, after des1, 2d
Create tests for parser :crit, active, 3d
Future task in critical line :crit, 5d
Create tests for renderer :2d
Add to mermaid :1d
Functionality added :milestone, 2014-01-25, 0d
section Documentation
Describe gantt syntax :active, a1, after des1, 3d
Add gantt diagram to demo page :after a1 , 20h
Add another diagram to demo page :doc1, after a1 , 48h
section Last section
Describe gantt syntax :after doc1, 3d
Add gantt diagram to demo page :20h
Add another diagram to demo page :48h
```
It is possible to set multiple dependencies separated by space:
To do so, start a line with the `section` keyword and give it a name. (Note that unlike with the [title for the entire chart](#title), this name is _required_.
You can add milestones to the diagrams. Milestones differ from tasks as they represent a single instant in time and are identified by the keyword `milestone`. Below is an example on how to use milestones. As you may notice, the exact location of the milestone is determined by the initial date for the milestone and the "duration" of the task this way: _initial date_+_duration_/2.
`dateFormat` defines the format of the date **input** of your gantt elements. How these dates are represented in the rendered chart **output** are defined by `axisFormat`.
### Input date format
The default input date format is `YYYY-MM-DD`. You can define your custom `dateFormat`.
The compact mode allows you to display multiple tasks in the same row. Compact mode can be enabled for a gantt chart by adding the compact flag to the gantt chart.
Comments can be entered within a gantt chart, which will be ignored by the parser. Comments need to be on their own line and must be prefaced with `%%` (double percent signs). Any text after the start of the comment to the next newline will be treated as a comment, including any diagram syntax.
Styling of the Gantt diagram is done by defining a number of CSS classes. During rendering, these classes are extracted from the file located at src/diagrams/gantt/styles.js
| mirrorActor | Turns on/off the rendering of actors below the diagram as well as above it | false |
| bottomMarginAdj | Adjusts how far down the graph ended. Wide borders styles with css could generate unwanted clipping which is why this config param exists. | 1 |
It is possible to bind a click event to a task. The click can lead to either a javascript callback or to a link which will be opened in the current browser tab. **Note**: This functionality is disabled when using `securityLevel='strict'` and enabled when using `securityLevel='loose'`.
- callback is the name of a javascript function defined on the page displaying the graph, the function will be called with the taskId as the parameter if no other arguments are specified.
