BPMN symbols explained: the complete 2.0 reference
BPMN 2.0 symbols fall into a few clear groups: events (circles), activities (rounded rectangles), gateways (diamonds), connecting flows (arrows), swimlanes (pools and lanes), and artifacts (data and notes). Learn these and you can read almost any BPMN diagram. This is the complete plain-English reference.
Events (circles)
Events are things that happen — they start, interrupt, or end the flow. The border tells you the position; the icon inside tells you the trigger.
| Event | Look | Meaning |
|---|---|---|
| Start event | Thin (single-line) circle | Where the process begins |
| Intermediate event | Double-line circle | Something that happens during the process |
| End event | Thick (bold) circle | Where a path finishes |
| Message event | Envelope icon | Sending or receiving a message |
| Timer event | Clock icon | Waiting for a time or date |
| Error event | Lightning icon | An error is thrown or caught |
Full detail and examples: BPMN events explained.
Activities (rounded rectangles)
An activity is work being done. The most common is the task — a single unit of work, named with a verb-noun phrase ("Approve request").
- User task — a person does it (little person icon).
- Service task — a system/automation does it (gears icon).
- Manual task — done offline, outside any system (hand icon).
- Script task — an engine runs a script.
- Sub-process — a collapsible activity (with a
+) that contains its own mini-diagram, used to hide detail.
Gateways (diamonds)
A gateway controls how the path branches or merges.
| Gateway | Marker | Meaning |
|---|---|---|
| Exclusive | X (or empty) | Take exactly one path based on a condition |
| Parallel | + | Take all paths at the same time |
| Inclusive | O (circle) | Take one or more paths |
| Event-based | Pentagon in circle | The path taken depends on which event happens first |
Full detail: BPMN gateways explained.
Connecting objects (the arrows)
- Sequence flow — a solid arrow. The order of steps within one process.
- Message flow — a dashed arrow with an open arrowhead. Communication between two participants (across pools).
- Association — a dotted line linking an artifact (like a note or data object) to a flow element.
Mixing these up is a classic beginner error — see common BPMN mistakes.
Swimlanes: pools and lanes
- A pool represents a participant (a whole organisation, system, or role).
- A lane is a subdivision inside a pool — usually a specific person, team or department — showing who performs each step.
Full detail: pools and lanes.
Artifacts
- Data object — a document/data that a task produces or needs (a page with a folded corner).
- Data store — a database the process reads from or writes to.
- Group — a dashed rounded box that visually clusters elements (no execution meaning).
- Text annotation — a comment attached to any element.
The 20% that covers 80% of diagrams
If you only remember six symbols: start event, task, exclusive gateway, sequence flow, end event, and pool/lane. That vocabulary reads the majority of real diagrams.
You don't have to memorise the rest to use them, though — describe your process to BPMN Studio and the AI places the correct symbols for you, which is a fast way to learn them in context. Next: how to create a BPMN diagram or what BPMN is.
Frequently asked questions
What are the four main categories of BPMN symbols?
BPMN symbols fall into four flow-element groups plus connecting objects and swimlanes: flow objects (events, activities, gateways), connecting objects (sequence flows, message flows, associations), swimlanes (pools and lanes), and artifacts (data objects, groups, annotations).
What does a diamond mean in BPMN?
A diamond is a gateway — a point where the process path splits or merges. An empty diamond or one with an X is an exclusive gateway (choose one path); a plus sign is a parallel gateway (all paths at once); a circle is an inclusive gateway (one or more paths).
What is the difference between a sequence flow and a message flow?
A sequence flow is a solid arrow showing the order of steps within one process (one pool). A message flow is a dashed arrow showing communication between two separate participants (across pools).
What do the different circles mean in BPMN?
Circles are events. A thin single-line circle is a start event, a double-line circle is an intermediate event, and a thick single-line circle is an end event. Icons inside (envelope, clock, lightning) show the trigger type: message, timer, error and so on.