What is a burndown chart?
Definition: Burndown chart is a graphical representation of the remaining work and the required time to complete a project. The chart is drawn on a timeline, with the X-axis representing the timeline of the project and the Y-axis representing the amount of work remaining.
It gives project managers a clear view of the project’s progress and an easy way to estimate its completion date since it is updated regularly to show the project's progress in real time.
Elements of a burndown chart
X-Axis represents the days left to complete the project.
Y-Axis represents the remaining work needed to be done. It displays the number of user story points or hours required to be worked for the project to be complete.
The ideal work line represents the estimated remaining work with ideal conditions. It is the best-case scenario for the project without any delays or complications and is estimated before it starts.
The actual work line represents the real progress of the project and the actual work remaining. Unlike the ideal line, it’s not an estimate but is updated regularly.
Teams compare these two lines to determine how much their work differs from the ideal work and if they are on schedule to complete the project. Comparing these two lines also gives them an insight into the bottlenecks in their progress.
The Start and End points are located at the top left and bottom right of the graph and indicate the point at which no work has been done and where the project is complete.
Types of burndown charts
There are two types of burndown charts: sprint and product burndown charts.
Sprint burndown charts are used in agile projects to track the progress of individual sprints. They display the user stories the team will be working on and the number of days the sprint will last.
Product burndown charts are used to track the progress of large projects. They focus on the project goals rather than individual sprints. This is why the X-axis represents the number of sprints instead of days, and the Y-axis represents the big features needed to be completed.
How to read a burndown chart
On the burndown chart, the ideal line and the actual work line start from the same point, indicating that no work has been done.
The two lines will have points on them, indicating how much effort is left on each given day for the project to be complete.
Throughout the project, the actual work line will deviate from the ideal line, indicating that the project isn’t going according to plan.
These deviations are standard and have different meanings.
- If the actual line is close to the ideal line, the team is doing well, and the project is on schedule.
- If the actual line is below the ideal line, the team will finish the project ahead of time, which is good. If this is frequent, the team has to reconsider changing sprint durations or increasing the amount of work.
- If the actual line is above the ideal line, the team will be behind schedule, meaning more effort is needed to get back on track.
- If the line doesn’t finish at the end point, the team stopped working on the project due to issues that couldn’t be resolved.
How to create a burndown chart
Create a Google Spreadsheet and name it after the product that will be worked on during the sprint. In this example, it will be Mindmesh.
The two core items needed for the burndown chart are the number of user stories/features and the number of days the sprint will last. In our example, five features over ten days.
Name the first column user story or feature. The second column will be the estimate.
The row beneath the estimate will represent the day of the sprint, and above it, put in the date.
Fill in the user story points names and, on Day 0, the estimated days/hours/weeks needed to complete them. The estimate will represent the effort needed to complete the story point translated into days.
Create two new rows, the remaining effort, and the ideal trend, and sum the numbers above with the “Sum” formula. Do this only for Day 0.
For every next day in the remaining effort row, use the “Sum” formula and subtract it from the initial remaining effort (in this case, 20) and drag it along the row.
When we insert the work done on each story over the ten days, the formula will subtract the work done from the estimated effort.
Since the sprint lasts for ten days, the ideal work done will be split up equally throughout the sprint.
To create the actual burndown chart select the whole estimate and ideal rows, go to the “Insert” tab and select “Chart”.
In the chart options, select “Line Chart” and tick the “Switch Rows/Columns” box.
In the end, the burndown chart should look something like this:
What is the difference between a burndown and a burnup chart?
A burndown chart shows the amount of work remaining, while a burnup chart shows how much work has been done and the progress made. It starts from the bottom of the graph and goes upwards.
They are both used in project management as they show two important sides of a project timeline.