Flowchart Symbols and Meanings: The Complete Reference

Flowchart symbols are standard shapes that tell readers what kind of step they're looking at. Five shapes cover most diagrams. An oval marks the start and end, and a rectangle marks an action. A diamond is a decision, a parallelogram is input or output, and arrows show the flow. The rest of the standard set adds detail for documents, databases, subprocesses, connectors and waits.

Quick steps: choose the right symbol in five questions

1. Does the flow begin or end here? Use a terminator (oval).
2. Is it a question with two or more answers? Use a decision (diamond).
3. Does data or material enter or leave the process? Use input/output (parallelogram).
4. Is it a whole procedure documented elsewhere? Use a predefined process (rectangle with double side bars).
5. None of the above? It's an action, so use a process (rectangle).

Flowchart symbols chart

The table covers the symbols you'll find in textbooks, standards and the shape libraries of most diagram tools.

Most of these shapes trace back to ANSI X3.5, the US standard, and ISO 5807:1985, the international one. Diagram tools add a few extras, so shape libraries differ slightly. The standards also define rarer symbols, such as loop limit, sort and collate. Skip those unless a style guide asks for them.

Which 5 flowchart symbols do you actually need?

Most process maps and study notes need only these five. Label them the same way every time.

• Terminator. Give every chart one clear start. Several ends are fine if each says what happened, such as "Refund issued" or "Claim rejected".
• Process. Start each label with a verb, such as "Check stock". If a box contains "and", it probably holds two steps, so split it.
• Decision. Write a short question, such as "In stock?", and label every exit. Two exits is the norm. Three work when answers can't overlap, like Low, Medium and High.
• Input/output. Use it when something crosses the process boundary: a form arrives, or a report goes out. The work in between is a process.
• Flow line. Put an arrowhead on every line, and run the main path top to bottom or left to right. Where lines must cross, draw a small hop.

When should you use the specialized symbols?

Use one only when the difference changes what your reader does or checks. Otherwise, a rectangle with a clear label reads faster.

• Audit and compliance charts benefit from document, multiple documents and manual operation. They show where paper and human handling happen, which is where auditors look for controls.
• Software and data charts benefit from database, display, manual input and preparation.
• Operations charts benefit from delay, merge and extract, which make waiting and batch handling visible.

If you use anything beyond the basic five, add a small legend in a corner.

Subprocesses and connectors: how to split a big flowchart

Large processes don't fit on one readable page. Two symbols help you break them up, and they do different jobs.

What is a subprocess (predefined process) symbol?

A subprocess symbol, formally called a predefined process, stands for a set of steps defined somewhere else. It's drawn as a rectangle with an extra vertical line inside each side. The main chart shows one box. The detail lives in its own flowchart, a written procedure or, in software, a function.

Take an online order flow. "Process payment" can be a single predefined-process box. Behind it sits a separate chart: validate the card, request authorization, handle a decline and record the transaction. Readers of the main chart see the big picture, and anyone who needs the payment detail opens the second chart.

When should you use a subprocess?

• The same steps repeat. An identity check used by password reset and account recovery should be drawn once and referenced twice.
• Detail hides the big picture. If twelve payment steps crowd out everything around them, collapse them into one box.
• Another team owns the detail. "Legal review" can point to the legal team's own procedure instead of copying it.
• You're charting a program. A call to a function or subroutine is a predefined process.

Don't use it for a single action. One step is just a process box.

How do you link a subprocess to its own flowchart?

1. Give the box and the detailed chart exactly the same name, such as "Process payment".
2. Add a reference inside or beside the box: a page number, a document ID or, in digital tools, a hyperlink.
3. Start the child chart with a terminator named after the subprocess. End it with one that hands control back, such as "Return to order flow".
4. Match the outcomes. A payment subprocess might end approved or declined. Add a decision right after the box in the main chart to route each result.
5. Note what goes in and what comes out, for example "Needs: order total. Returns: approved or declined."

Subprocess or off-page connector: what's the difference?

An off-page connector continues the same flow on another page, and the flow doesn't come back. A subprocess is a detour: the flow enters the detailed chart, then returns to the next step in the main chart. Use connectors when the page runs out of room. Use subprocesses when a step deserves its own chart.

What are the most common flowchart symbol mistakes?

1. A parallelogram for a process step. "Calculate tax" is an action, so it belongs in a rectangle. Keep parallelograms for data entering or leaving.
2. Decisions with unlabeled exits. Two bare arrows leaving a diamond force readers to guess. Label every exit.
3. Two questions in one diamond. "In stock and paid?" hides which check failed. Use two diamonds.
4. Paths that just stop. Every path should end at a terminator or loop back to an earlier step.
5. Document symbols for all data. A document is something a person reads. Stored records belong in a database cylinder.
6. Text in connector circles. Connectors carry only a matching letter or number.
7. Mixed levels of detail. "Handle the customer" next to "Click Save" confuses readers. Keep one level, and push detail into subprocesses.

How do swimlanes work with flowchart symbols?

A swimlane flowchart adds one lane per person, team or system. Microsoft Visio calls it a cross-functional flowchart. Symbols keep their usual meanings, and the lanes show who does each step.

• One lane per actor. Name each lane at its start: the left edge for horizontal lanes, the top for vertical ones.
• Place each step in the doer's lane. If two roles share a step, pick the accountable one or split the step.
• Keep the reading direction. Horizontal lanes read left to right. Vertical lanes read top to bottom.
• Order lanes by first involvement. The customer or requester often goes in the top lane.
• Treat lane crossings as handoffs. Handoffs are common places for waiting and dropped work, so review them first.

If you need more than six or seven lanes, split the chart into subprocesses. For role-based process maps, see our workflow diagram guide.

BPMN vs classic flowchart symbols: what's the difference?

BPMN (Business Process Model and Notation) is a stricter notation for business processes. The Object Management Group maintains it, and it's also published as ISO/IEC 19510. BPMN reuses familiar shapes but gives each a precise meaning, so process software can analyze diagrams and, in some cases, run them.

Use a classic flowchart when your audience is broad and the goal is shared understanding. Use BPMN when process analysts, automation tools or compliance teams need exact meanings.

How do you make a flowchart readable and accessible?

• Don't rely on color alone. Shape and label should carry the meaning, as the WCAG "Use of Color" success criterion requires.
• Check contrast. WCAG 2.1 asks for 4.5:1 contrast for normal text and 3:1 for lines and shapes that carry meaning.
• Write short labels that stay readable at display size. Use verbs for processes, questions for decisions and no unexplained abbreviations.
• Split big charts. Past roughly 20 to 25 symbols, most charts read better as a main chart plus subprocesses.
• Provide a text version. Add short alt text, then list the steps and decision paths near the image. W3C guidance on complex images recommends this.
• Offer a static version of animated charts. Motion helps many viewers, but some people prefer reduced motion.

Faster option: let AI build the flowchart for you

Drawing symbols by hand is the slow part. With an AI flowchart maker like Infogiph, you describe the process in plain English. You get an animated, fully editable diagram, usually in about 5 to 15 seconds.

The AI applies the conventions that make a chart readable: a logical order, short labels, even spacing and clear connectors. Then you finish it on the canvas:

1. Describe the process, for example "Expense approval: employee submits, manager reviews, finance pays or returns it."
2. Pick a layout from the Diagram style menu. Pipeline and Steps suit linear processes, and Tree suits branching logic.
3. Click any node to change its label or icon, and set the connection color.
4. Export a PNG or SVG for documents, or an animated GIF or MP4.

One honest caveat: Infogiph draws steps as labeled icon nodes in its own clean style, not as exact ISO 5807 shapes. That suits slides, wikis, onboarding guides and social posts. When a course or auditor requires strict ISO shapes, use this guide as your checklist in Word, PowerPoint or Google Docs.

The free plan includes 5 AI generations in total and unlimited exports in all four formats, with a small Infogiph watermark. No credit card is needed, and you sign in with Google. Pro costs $12 a month, or $9 a month billed yearly, and removes the watermark. For a head start, open the approval workflow template or the decision tree template.

FAQ

What are the four basic flowchart symbols?

The oval (terminator) marks start and end, and the rectangle is a process step. The diamond is a decision, and the parallelogram is input or output. Arrows connect them to show the order.

Is the parallelogram for input or output?

Both. It marks data crossing the process boundary in either direction. Let the label say which, such as "Receive application" or "Send receipt".

What's the difference between a process and a predefined process?

A process box is one action at the current level of detail. A predefined process, or subprocess, stands for a whole procedure documented in its own chart. The flow returns to the main chart when that procedure finishes.

Is there a flowchart symbol for a loop?

Basic flowcharts draw a loop as a decision whose arrow points back to an earlier step. Programming flowcharts often use a preparation hexagon to set up the loop counter. ISO 5807 also defines a pair of loop limit symbols.

Do I have to follow ISO 5807 exactly?

Only when a course, client or regulator requires it. For internal documents, consistency matters more than strict compliance. Use the basic shapes the same way every time, and add a legend for anything unusual.

For worked diagrams that put these symbols to use, browse our flow chart examples and decision tree examples.