Gantt chart

Gantt charts get a bad reputation from being used as commitments rather than as plans. Used as a plan, they are good at one specific thing: showing which tasks cannot start until another finishes.

Mermaid has a Gantt syntax, so the chart lives in the page and changes in seconds.

#When to reach for one

• Project plans with real dependencies rather than a wish list.

• Migration and cutover planning, where sequence is everything.

• Communicating a schedule to people who will not open a project tool.

#How to draw it in Capable

#A worked example

A migration plan with dependencies and a milestone:

The source, which you can paste into a new diagram and edit:

gantt
  title Platform migration
  dateFormat YYYY-MM-DD
  axisFormat %d %b

  section Preparation
  Inventory current system :done, inv, 2026-09-01, 10d
  Agree target architecture :active, arch, after inv, 7d

  section Build
  Provision environment :prov, after arch, 5d
  Migrate data :crit, data, after prov, 14d
  Parallel run :par, after data, 10d

  section Cutover
  Freeze and switch :milestone, cut, after par, 0d
  Decommission old system :dec, after cut, 5d

#A few things that catch people out

• Dependencies are the reason to draw one. A Gantt chart with no dependencies is a list with bars.

• Mark the critical path; without it every bar looks equally important.

• Keep it coarse. A Gantt chart with sixty rows is a project plan nobody reads.

#Related

A plan you can change is a plan people trust.