Free Online Gantt Chart Editor

Plan and visualize project timelines with Gantt charts. Track tasks, dependencies, and milestones using simple text syntax.

Create Gantt Charts

Key Features

  • Define tasks with start and end dates
  • Set task dependencies and milestones
  • Visual timeline representation
  • Real-time chart updates
  • Export to SVG or PNG formats
  • Share project timelines via URL

Common Use Cases

  • Plan project schedules
  • Visualize task dependencies
  • Track project milestones
  • Create sprint timelines
  • Document release plans
  • Communicate project status

Example Gantt Chart

gantt
    title Project Timeline
    dateFormat YYYY-MM-DD
    section Planning
    Requirements :done, req, 2024-01-01, 2024-01-14
    Design :active, des, 2024-01-15, 2024-01-28
    section Development
    Backend :crit, backend, 2024-01-29, 2024-02-18
    Frontend : frontend, 2024-02-05, 2024-02-25
    section Testing
    QA Testing : testing, 2024-02-26, 2024-03-10
    section Deployment
    Launch :milestone, launch, 2024-03-15, 0d
Try this example

Why Use This Gantt Chart Editor?

Our free online gantt chart editor makes it easy to create professional diagrams using simple text-based syntax. No installation required - just start typing and see your diagram render in real-time.

Built on Mermaid.js, this editor provides instant preview, SVG/PNG export, and URL sharing capabilities. Perfect for developers, technical writers, project managers, and anyone who needs to create clear, professional diagrams quickly.

How to Create a Gantt Chart

  1. Start with 'gantt' keyword and optionally set date format and axis format for your timeline
  2. Add a title for your Gantt chart to describe the project or timeline being visualized
  3. Define sections to group related tasks (e.g., Planning, Development, Testing)
  4. Add tasks with labels and duration using dates (YYYY-MM-DD format) or relative time
  5. Set task dependencies using 'after taskId' to show which tasks must complete before others
  6. Mark milestones with zero duration to highlight important project dates
  7. Use 'active' or 'done' keywords to show task status and progress
  8. Review the timeline visualization and adjust task durations or dependencies as needed

Best Practices for Gantt Charts

  • Use consistent task naming: Adopt a clear naming convention for all tasks (e.g., verb + object format)
  • Group related tasks: Organize tasks into logical sections or phases for better readability
  • Show realistic dependencies: Only link tasks that truly depend on each other to avoid over-constraining
  • Include milestones: Mark key project dates like reviews, releases, or deliverables
  • Keep granularity appropriate: Break tasks into 2-5 day chunks for active work, weekly for future work
  • Update regularly: Gantt charts are living documents - mark completed tasks and adjust timelines
  • Don't over-specify: Early project phases can have broader tasks; add detail as you approach execution
  • Consider critical path: Identify and highlight the sequence of tasks that determines project duration

Advanced Gantt Chart Features

Critical Path Highlighting

Mark tasks as critical using the 'crit' keyword to highlight the sequence of tasks that cannot be delayed without affecting the project end date. Essential for project management and risk assessment.

Task Status Tracking

Use 'done', 'active', and 'crit' keywords to show task completion status. This helps track project progress and identify what's completed, in progress, or upcoming.

Multiple Date Formats

Configure custom date and axis formats using dateFormat and axisFormat directives. Supports various formats from YYYY-MM-DD to custom representations.

Task Dependencies

Create complex dependency chains with 'after taskA taskB' syntax to show tasks that depend on multiple predecessors. Perfect for modeling parallel workstreams that converge.

Common Gantt Chart Mistakes

  • ⚠️Using incorrect date formats - Mermaid requires YYYY-MM-DD format or relative durations like '5d' for 5 days
  • ⚠️Creating circular dependencies - Task A can't depend on Task B if Task B depends on Task A
  • ⚠️Too many tasks - More than 20-30 tasks makes the chart overwhelming; group or break into multiple charts
  • ⚠️Missing critical milestones - Always mark important dates like launch dates, reviews, or deadlines
  • ⚠️Unrealistic task durations - Verify task lengths against actual capacity and complexity
  • ⚠️Ignoring task status - Use 'done', 'active', or 'crit' keywords to show progress and critical tasks
  • ⚠️Not accounting for dependencies - Tasks that require others to complete should use 'after' syntax
  • ⚠️Forgetting buffer time - Real projects have delays; build in slack time for unexpected issues

When to Use Gantt Charts vs Other Diagrams

Gantt charts are specifically designed for project scheduling and timeline visualization. Use them when you need to show task durations, dependencies, and project phases over time. They're essential for project planning, resource allocation, and schedule communication.

Choose flowcharts when you need to show process logic rather than time-based scheduling. Use sequence diagrams when focusing on interactions between components rather than task timelines. For showing project tasks in a simple list without time dimensions, a checklist or task board is more appropriate.

Gantt charts excel in project management contexts where understanding the critical path, resource allocation over time, and schedule dependencies are crucial. They're widely used in software development (sprint planning), construction (project schedules), and any domain where coordinating multiple time-dependent tasks is essential.

Frequently Asked Questions

Common questions about using the Mermaid Viewer and creating diagrams