A Cumulative Flow Diagram (CFD) is a visual tool that helps teams track work across different stages of a process; like To Do, In Progress, and Done. It’s a key part of Agile and Kanban project management. At a glance, a CFD shows you how smoothly work flows through your system and helps you spot problems early.
In this guide, I will explain what a CFD is, how it works, and why it matters, with samples.
What Does a Cumulative Flow Diagram Show?
Think of a CFD like a time-lapse of your workflow. It captures the number of tasks in each stage of work on a daily basis.
Here is a sample CFD:
In this chart:
- The Top green layer shows how many tasks are done.
- The middle orange layer shows tasks currently in progress.
- The bottom blue layer shows tasks that haven’t started yet.
The height of each layer shows the number of tasks in that category. The total height of the graph shows the total number of tasks in the system.
Why Use a Cumulative Flow Diagram?
A Cumulative Flow Diagram is a powerful tool for Agile and Kanban teams who want visibility into their actual workflow.
It helps you:
- Visualize work across every stage of your process
- Track progress over time and identify trends
- Spot bottlenecks early, before they become major issues
- Analyze delays and areas where work is getting stuck
- Measure throughput, helping you see how much work is completed
- Understand workflow balance between starting, doing, and finishing tasks
CFDs are more insightful than burn-down or velocity charts. While those focus only on how much work is left or completed, CFDs show what’s happening at every step, from To Do to Done. They give an honest view of your system’s performance, highlighting both flow and friction.
Whether you’re leading a team or optimizing a process, a CFD gives you the data you need to improve, not just report.
Key Parts of a Cumulative Flow Diagram
Understanding a CFD starts with knowing what each part of the chart represents.
The following are the key elements of a CFD:
1. Time (X-Axis): The horizontal axis tracks time, typically in days, weeks, or sprints. This allows you to see how your workflow changes over time.
2. Work Items (Y-Axis): The vertical axis shows the number of tasks or work items currently in your system. This includes all stages—To Do, In Progress, and Done.
3. Stacked Layers: Each colored band represents a stage in your workflow, such as:
- To Do (work not yet started)
- In Progress (actively being worked on)
- Blocked (optional but helpful in identifying stuck tasks)
- Done (completed work)
The thickness and shape of each layer reveal how smoothly the work is flowing. Sudden bulges or flattening can indicate bottlenecks, stalled work, or uneven task distribution.
How to Read a Cumulative Flow Diagram
Let’s walk through a few examples.
1. Steady Progress
If each layer grows smoothly, it means tasks are moving through the system at a steady pace. That’s good.
2. Widening “In Progress” Layer
If the In Progress layer keeps growing while others stay flat, you’ve got a problem—too much work is stuck in progress.
Here is what that might look like:
This shows that Work In Progress (WIP) is piling up, which slows the team down. That’s a clear signal to limit WIP or address blockers.
3. Flat “Done” Layer
If the Done section isn’t growing, your team isn’t completing tasks. You may need to reduce scope, improve flow, or clear bottlenecks.
Here is a chart of how completed tasks grow over time:
If that line flattens, it means nothing is getting finished.
How to Create a Cumulative Flow Diagram
You can create a Cumulative Flow Diagram using data from task-tracking tools like Jira, nTask, monday.com, Asana, ClickUp, or even a simple spreadsheet.
The following is a step-by-step process to create a CFD:
Step 1: Track Tasks Daily
Every day, record the number of tasks in each workflow stage:
- To Do (not started)
- In Progress
- Blocked (optional but helpful)
- Done (completed)
Make sure you’re consistent with timing, and capture data at the same time each day for accuracy.
Step 2: Stack the Data
For each day, stack the task counts in the order of your workflow. This creates a layered view where each segment represents a stage in the process.
Step 3: Create the Chart
Use a spreadsheet (Excel or Google Sheets) or built-in reporting tools in apps like Jira to create a stacked area chart.
Now you have a visual representation of your workflow.
Cumulative Flow Diagram Vs Burndown Charts
Burndown charts are simple tools that show how much work remains over time. They help track progress toward a deadline, but they have one significant limitation: they only show what’s left to do. They don’t show where work might be getting stuck.
A Cumulative Flow Diagram gives a more complete view of your workflow. It shows:
- Tasks not started
- Tasks in progress
- Tasks that are stuck or piling up
- Tasks that are finished
This makes it easier to:
- Identify bottlenecks early
- Understand how work flows through your team
- Spot where delays happen
- Make better decisions to improve delivery
While burn-down charts focus on speed, CFDs concentrate on flow and stability. They help you fix problems, not just track them. If your team wants to work smarter and spot issues faster, a CFD is the better tool.
Common CFD Patterns and What They Mean
| Pattern | What It Means | What To Do |
| In Progress grows faster than Done | Bottleneck in finishing work | Limit WIP, fix blockers |
| To Do stays high | Team not starting new work | Check prioritization or clarity |
| All layers flat | No change or stalled project | Investigate blockers |
| Steady Done growth | Healthy flow | Keep doing what works |
How CFDs Help You Improve
Here is how the cumulative flow diagram helps you improve your workflow:
1. Spot Bottlenecks Early
A widening In Progress section signals that tasks are piling up. This usually means something is blocking your team, maybe unclear requirements, too many tasks at once, or slow approvals. A CFD helps you spot these issues early so you can remove blockers and keep work moving.
2. Forecast Delivery Dates
By tracking how quickly the Done section grows, you can predict when future work will be completed. This helps with planning, setting realistic deadlines, and managing stakeholder expectations.
3. Improve Flow Efficiency
CFDs shift your focus from “how fast are we going?” to “how smoothly are we working?” Instead of chasing speed, you reduce delays, improve handoffs, and keep work flowing steadily, leading to better long-term results.
4. Visualize the Entire Workflow
Unlike other charts, CFDs show every stage of work. This gives you a complete picture of your process, making continuous improvement easier.
Summary
A cumulative flow diagram is more than just a chart; it is a window into how your team works. It shows how much is getting done, where work is getting stuck, and how your process is performing. With a glance, you can spot bottlenecks, track progress, and improve flow.
If you use a Kanban board or manage tasks in stages, start tracking a CFD. It’ll tell you what no status meeting ever could and help your team work smarter.
Further Reading:
- What is Agile Methodology in Project Management?
- What is a Burndown Chart in Scrum?
- What is a Burn-up Chart in Agile Project Management?
- Burnup Vs Burndown Charts
- Control Chart versus Run Chart
Reference:
I am Mohammad Fahad Usmani, B.E. PMP, PMI-RMP. I have been blogging on project management topics since 2011. To date, thousands of professionals have passed the PMP exam using my resources.
