A Gantt chart is a horizontal bar chart that lays a project out against time. Each task is a bar whose position and length show its start date and duration, and the chart makes schedules, overlaps, dependencies, and milestones immediately visible. It is the default view for project planning across software, construction, marketing, and operations.
Diagramming AI turns a plain-English project description into an editable Mermaid Gantt chart in seconds. Describe your phases, tasks, and durations, and the AI generates ready-to-edit chart code — including sections, dependencies, and milestones — which you can then refine conversationally.
A Gantt chart organizes work into rows of tasks plotted along a time axis. Tasks can be grouped into sections (such as phases of a project), and dependencies are expressed by chaining one task to start after another finishes. Zero-duration milestones mark important checkpoints like a launch date or a sign-off.
In Mermaid, each task has an identifier, an optional status (done, active, or crit for critical), and either an explicit start date or an "after" reference to another task. Durations are written in days or weeks. This makes it easy to express a realistic plan where later tasks automatically shift if an earlier task’s duration changes.
Describe your project as a list of phases and the tasks within each, with rough durations and any "this must finish before that starts" dependencies. Diagramming AI converts that into a Mermaid Gantt chart, choosing sensible task identifiers and wiring up the dependencies for you.
Then iterate in the chat: "add a two-week testing phase before launch", "mark the security review as critical", or "push the rollout to start after QA". Each instruction updates the editable chart, and you can export the timeline or paste the Mermaid into your planning docs.
Scenario: A multi-phase software project with design, development, and release sections, chained dependencies, and a launch milestone.
Instruction text for AI
Create a Gantt chart for a software project with three phases: Design (requirements and UI design), Development (backend and frontend), and Release (QA and launch). Chain the tasks so each starts after the previous one, and add a launch milestone.Generated Diagram (Mermaid)
gantt
title Software Project Plan
dateFormat YYYY-MM-DD
axisFormat %b %d
section Design
Requirements :done, req, 2026-01-05, 7d
UI design :active, ui, after req, 10d
section Development
Backend API : be, after ui, 21d
Frontend : fe, after ui, 18d
section Release
QA testing :crit, qa, after be, 10d
Launch :milestone, after qa, 0dScenario: A product-launch marketing plan with overlapping content, paid, and PR workstreams running in parallel.
Instruction text for AI
Draw a Gantt chart for a 6-week product launch marketing campaign with three parallel workstreams: content creation, paid advertising, and PR outreach, ending with launch day.Generated Diagram (Mermaid)
gantt
title Product Launch Campaign
dateFormat YYYY-MM-DD
axisFormat %b %d
section Content
Blog posts :c1, 2026-02-02, 14d
Email sequence :c2, after c1, 7d
section Paid Ads
Creative assets :p1, 2026-02-02, 10d
Ad campaign live :p2, after p1, 18d
section PR
Press outreach :pr1, 2026-02-09, 14d
Launch day :milestone, after p2, 0dScenario: A building project with strictly sequential phases, illustrating a critical path where every task depends on the one before it.
Instruction text for AI
Generate a Gantt chart for a small construction project with sequential phases: site preparation, foundation, framing, roofing, and interior finishing, where each phase must finish before the next begins.Generated Diagram (Mermaid)
gantt
title Construction Schedule
dateFormat YYYY-MM-DD
axisFormat %b %d
section Build
Site preparation :crit, sp, 2026-03-02, 7d
Foundation :crit, fo, after sp, 14d
Framing :crit, fr, after fo, 21d
Roofing : ro, after fr, 10d
Interior finishing: fi, after ro, 18dA Gantt chart is used for project planning and scheduling. It shows each task as a bar on a timeline so you can see start and end dates, how long tasks take, where they overlap, how they depend on one another, and when key milestones occur. It is widely used in software, construction, marketing, and operations.
Yes. Describe your project phases, tasks, durations, and dependencies in plain English, and Diagramming AI generates an editable Mermaid Gantt chart with sections and milestones. You can then refine it through follow-up chat instructions and export the timeline.
In Mermaid, a task can start on an explicit date or "after" another task using that task’s identifier. Chaining tasks with "after" creates dependencies, so if you change an earlier task’s duration, every dependent task shifts automatically. This keeps the schedule consistent as the plan evolves.
A milestone is a zero-duration marker for an important checkpoint such as a launch or sign-off. In Mermaid you add it with the "milestone" keyword and a duration of 0d, optionally placed "after" the task it should follow. Diagramming AI adds milestones automatically when you mention them.
Continue with related guides, browse templates, or start building your own diagram in Diagramming AI.