What is a Gantt chart?
Organising a party. Finishing an assignment. Getting out the door before the bus comes. Every one of these has lots of little jobs that need to happen in the right order, at the right time. A Gantt chart helps you see all of those jobs at once.
Projects and tasks
A project is a job with a clear start and a clear finish. Big projects are made of smaller steps called tasks. Planning a project starts with breaking it into tasks.
So what is a Gantt chart?
A Gantt chart is a bar chart made for planning projects. Tasks are listed down the left side. Time runs across the top. Each task gets a bar that shows when it starts and how long it takes.
Gantt charts are named after Henry Gantt, an American engineer who made them popular more than 100 years ago. People still use them today to plan buildings, bridges, films and video games.
Parts of a Gantt chart
This chart plans a school morning. Click each word to see where that part is on the chart.
Pick a word above to start exploring.
Flow chart or Gantt chart?
You have already made a flow chart for cooking a cheese toastie. Flow charts and Gantt charts are both planning tools, but they answer different questions.
Flow chart
A flow chart answers:
- What are the steps?
- What order do they go in?
- What happens if something goes a different way?
Gantt chart
A Gantt chart answers:
- When does each task happen, and how long does it take?
- Which tasks can happen at the same time?
- Who is doing each task, and when will the project be finished?
Example 1: Building a cubby house
Imagine you are building a cubby house in the backyard these school holidays, all by yourself. Step through the plan to watch the Gantt chart being built, one task at a time.
One person, one pair of hands
Notice how the bars make a staircase shape? When you are the only person working, you can only do one busy task at a time, so each task has to wait its turn. The one overlap is while the paint dries, because drying paint doesn't need you.
Read the chart
Answer each question in your head (or in your book) before you check.
How many days does the whole cubby house project take?
12 days. The milestone diamond sits at the end of Day 12.
Which tasks take the longest?
"Build the floor" and "Build the walls". Their bars are 2 columns long, so each takes 2 days.
It rains on Day 7 and you can't work. What happens to the rest of the plan?
Building the walls finishes a day late. Everything that depends on the walls (follow the arrows) moves one day later too, so the cubby is finished on Day 13 instead of Day 12.
Example 2: A team bake sale
Mia, Leo, Ava and Sam are running a bake sale to raise money for the school library. Their Gantt chart has a colour for each person, so everyone can see who is doing what, and when.
Why teams use Gantt charts
When a team works together, different people can do tasks at the same time. These are called parallel tasks. Look at Tuesday of Week 1: four tasks are happening at once!
A Gantt chart helps a team see who is doing what, spot when someone is too busy, and make sure nothing is forgotten. Click a name above to spotlight that person's tasks.
Why is there a gap before "Buy ingredients"?
The team waits until the week of the sale, so the food is fresh. Gaps in a Gantt chart can be on purpose.
Read the chart
Who is the busiest person in the team?
Sam. Not counting sale day, Sam has 4 days of tasks: making price labels (2 days), buying ingredients and baking cookies.
Leo finishes his tasks on Thursday of Week 1. What could he do next?
Help someone else! A Gantt chart makes it easy to spot who has spare time. Leo could help Sam with the price labels or Ava with the baking.
Why do four arrows point to "Bake sale!"?
The sale depends on four tasks. It can't happen until the posters are up, the stall is set up, and both the cupcakes and cookies are baked.
Switch to "One person does everything". How much longer does the project take?
4 more school days: 14 days instead of 10. Working alone, you can only do one task at a time, so nothing happens in parallel.
Checkpoint
Nine questions to check you're ready to build your own Gantt charts. Your score goes into your PDF, and you can try again as many times as you like.
Task 1: Cooking a cheese toastie
You already worked out the steps for a cheese toastie in your flow chart. Now add the one thing a flow chart doesn't show: time. Your timeline for this chart is in minutes.
Turn your flow chart into a Gantt chart
Open your cheese toastie flow chart. Each flow chart symbol becomes a different part of your Gantt chart.
Careful with diamonds. In a flow chart, a diamond is a decision. In a Gantt chart, a diamond is a milestone. Same shape, different meaning!
The start is minute 0, the left edge of your timeline.
Every process box becomes a task with its own bar.
An arrow shows order. Add a dependency arrow when one step really must finish before the next one starts.
A decision is not a bar. Think about the extra time it might add. If the toastie isn't golden, it needs to cook for longer.
The end becomes a milestone, like "Toastie ready!".
How to build your chart
- Add a task for each process box in your flow chart. Use the task bank, or type your own task.
- Drag the middle of a bar to move it to when the task starts. Drag the right edge to stretch it to how long the task takes. Every new task starts 1 minute long.
- Is it a waiting task, like the sandwich press heating up? Change its type, then plan something to do at the same time.
- Add dependency arrows in the task editor, and a milestone for when your toastie is ready.
- Fix anything in the red warning list, tick off the checklist, then answer the three questions.
Explain your plan
Finishing next lesson? Click Save my work at the top of the page and keep the file. Next lesson, click Open saved work to carry on.
Task 2: Going on a holiday
Time to pack your bags! Use the country you researched in your Travelling to a Country task to plan a 4-day holiday. This timeline is in hours, from 12am on Day 1 to midnight at the end of Day 4.
Your trip
Get out your Travelling to a Country task. Copy the details you found into the boxes below.
Round to the nearest hour.
Things to think about
- Getting there. How long is the flight? You also need time to get to the airport, check in and collect your bags.
- Sleep. You need to sleep every night. The shaded columns show night time, from 8pm to 6am.
- Meals. Breakfast, lunch and dinner all take time.
- Things to see and do. Which landmarks, foods and activities did you find in your research?
- Getting home. Your holiday isn't finished until you are back home.
Challenge: time zones. When you land, the local time might be different from home. If your country is in a different time zone, show local times in your chart and explain how you worked them out in your answers.
Explain your plan
Submit your Gantt charts
Check your work, rate yourself against the rubric, then create your PDF. Upload the PDF to your assignment so your teacher can mark it.
Your details
Your progress
Rate your work
For each row, click the description that best matches your work. Be honest: your teacher will compare your rating with theirs.
Create your PDF
Your PDF includes both Gantt charts, a table of every task, your checklists, your answers, your checkpoint score and your self-rating.
Start again from scratch
This clears everything on this page: your checkpoint quiz score, both Gantt charts, your written answers, your self-rating and your details. It cannot be undone. If you might want your work back, click Save my work first.
Custom Gantt
Plan anything you like: a science project, a birthday party, a game jam, a week of training. Choose your time unit and how long the timeline is, add the people involved, then build your chart. This page is separate from the assessment tasks and has its own save and PDF buttons.
Set up your chart
Between 2 and 240. This sets the number of columns in the chart.