How to Read a Gantt Chart

Learn to interpret every element of a Gantt chart in 6 simple steps.

  1. Scan the task list — The left column lists every task, usually grouped by phase (Discovery, Design, Build, Launch).
  2. Read the timeline — The top axis shows days, weeks, or months. All tasks are plotted against this axis.
  3. Check bar positions — Bar start = task start date. Bar end = task end date. Bar length = task duration.
  4. Follow dependency arrows — Arrows from right to left show which tasks depend on others finishing first.
  5. Spot milestones — Diamond markers represent zero-duration events like deadlines or launches.
  6. Identify the critical path — Red/highlighted tasks form the longest chain — delay any and the whole project slips.