What is a swimlane diagram?
A swimlane diagram is a process flowchart organized into horizontal (or vertical) bands called lanes, like the lanes of a swimming pool. Each lane belongs to an actor (a role, team, department, customer, supplier or IT system), and every step is drawn in the lane of the actor who performs it. Also known as a cross-functional flowchart or Rummler-Brache diagram, it is the standard way to map processes that cross organizational boundaries.
Why use swimlanes
- Clear responsibilities: anyone can see who owns each step, which supports RACI discussions and procedures.
- Visible hand-offs: each arrow crossing a lane is a hand-off, where work waits, information gets lost and errors creep in.
- Better procedures: the diagram maps directly to the "responsibilities" section of an SOP.
- System design: lanes for IT systems show where data is entered, transferred or re-keyed.
Swimlane diagram example
The example shows how a supplier change notification moves between the supplier, purchasing, quality and engineering. Quality decides whether the change affects product quality; if it does, engineering assesses the technical impact before quality approves the change and updates the approved supplier list. Purchasing then confirms the decision to the supplier. Six arrows cross lanes: six hand-offs to manage.
To quantify hand-offs and waiting time, list the same steps in a workflow map. For a single-team process, a process flowchart is simpler.
Tips for effective swimlane diagrams
- Limit the lanes to the actors that matter, typically 3 to 7. Group minor contributors.
- Order the lanes so most arrows flow between neighbouring lanes. Put the customer at the top.
- Keep time flowing left to right and avoid arrows going backwards except for genuine rework loops.
- Mark rework loops: every "No" that sends work back is a cost of poor quality.
How to use this Swimlane Diagram tool
- Define the process and roles. Name the process and set up one lane for each role, team or system involved. Click a lane name to edit it.
- Add the starting event. Place the start in the lane where the process is triggered.
- Add steps in the right lanes. Select a step and add the next one. It is placed to the right and connected; change its lane in the editor or drag it up or down into another lane.
- Add decisions and connections. Use decision shapes for questions, label their exits, and drag from a blue handle to connect steps.
- Review hand-offs. Look at every arrow that crosses lanes. Each one is a hand-off, a potential delay and a candidate for improvement.
- Export and share. Export to PDF or PNG for procedures and training, or Excel for a step list by role.
Frequently asked questions
What is a swimlane diagram?
A swimlane diagram, also called a cross-functional flowchart or Rummler-Brache diagram, is a process flowchart divided into lanes. Each lane represents a role, team, department or system, and each step sits in the lane of whoever performs it.
When should I use a swimlane diagram instead of a flowchart?
Use a swimlane diagram whenever more than one role or department is involved. The lanes make hand-offs visible, and hand-offs are where delays, rework and lost information usually happen.
Should lanes be people, roles or departments?
Use roles or functions rather than named people, so the diagram stays valid when people change. Departments work for high-level maps; roles are better for detailed process design.
Can swimlanes be vertical?
Yes, both orientations are common. This tool uses horizontal lanes with the process flowing left to right, which fits long processes on a wide screen and in landscape documents.
How do I reduce hand-offs?
Count the arrows that cross between lanes. Ask whether each hand-off adds value, whether steps can be combined in one role, and whether approvals can be run in parallel. A workflow map adds wait times to quantify the impact.
Can I export the swimlane diagram?
Yes. Export a PDF report, a PNG image, or an Excel or CSV list of steps by lane, or save a file to reopen and edit it later. It is free with no sign-up.