Flowchart Symbols and Meanings: The 10 Standard Shapes Explained
Ever started a flowchart, then froze on a simple question: do I use the rectangle here, or the diamond? That tiny moment of doubt is more draining than it looks.
When the meaning of a symbol is fuzzy, your diagram makes sense to you but not to anyone else. You spend real time on it, and someone still asks, "Wait, what does this part mean?" That back-and-forth is exactly what a good diagram should prevent.
Here is the good news. The symbols you actually use at work come down to just 10. And on day one, you really only need four of them.
This guide walks through the 10 main flowchart symbols defined in the ISO 5807 standard (JIS X 0121 in Japan) — what each one means and how to use it, with a reference table and worked examples. By the end, you will pick the right shape without second-guessing yourself.
What you will learn
- A reference table of the 10 standard flowchart symbols (ISO 5807)
- How to use the terminator, process, decision and flow line correctly
- Worked examples that combine the symbols into real flowcharts
- 3 common symbol mistakes beginners make, and how to avoid them
Flowchart Symbols at a Glance: The 10 Standard Shapes
Let's get straight to the point. Flowchart symbols have fixed shapes and meanings, defined in the ISO 5807 standard (JIS X 0121 in Japan). In practice, these are the only 10 you need to know.
Symbols are the shared language of a diagram. Invent your own shapes and you quietly confuse the reader. The flip side is encouraging: simply choosing the right symbol can turn your diagram into one that actually gets your point across.
| Symbol | Shape | Meaning | Typical use |
|---|---|---|---|
| Terminator | Rounded rectangle / oval | Start and end of the flow | Place one at the entry and one at the exit of every diagram |
| Process | Rectangle | A single task or action | A concrete step such as "Create the quote" |
| Decision | Diamond | A conditional branch | A Yes/No fork such as "Approved?" |
| Flow line | Solid arrow | Order and direction of steps | Connects symbols to show how the flow moves |
| Data (I/O) | Parallelogram | Data input or output | "Enter the order details", "Output the result" |
| Document | Rectangle with a wavy base | A paper or document output | "Issue the invoice" and other paper/PDF outputs |
| Preparation | Hexagon | Setup or initialization | Initializing a variable, prep work before the main steps |
| Predefined process | Rectangle with double side bars | A set of steps defined elsewhere | A subroutine, or a task detailed in another diagram |
| Loop limit | Paired hexagon-like shapes | Start and end of a repeated block | "Repeat until every record is processed" |
| Connector | Small circle | Links distant flow lines | Diagrams that span pages, or where you want to avoid crossings |
Of these 10, learn the top four first — terminator, process, decision and flow line. More than 80% of real-world flowcharts are built from those four alone. For the other six, it is perfectly fine to come back to this table whenever you need them.
Minami
Process improvement lead
Honestly, hearing "10 symbols" makes me tense up a little. Do I have to memorize them all up front?
Spark
DrillSpark consultant
Relax, you don't! Start with just the top four — that covers about 80% of everyday work. For the rest, the rule is simply "look it up when it comes up." The trick is to keep the first step light.
The 4 Essential Symbols and How to Use Them
Let's start with the four symbols you will reach for far more than any others. Get these right and you already have the foundation of a readable flowchart.
Terminator (rounded rectangle): the start and end of the flow
The terminator marks the entry and exit of a flowchart. Draw it as a rounded rectangle (or an oval) and write the starting or ending event inside — "Start", "End", or something like "Order received" and "Shipped". Every diagram has exactly one start, but it can have several ends if different branches finish in different ways.
Process (rectangle): the most common symbol, one task each
The process is the symbol you will use most. Inside a rectangle, write a single concrete action ending in a verb, such as "Check the stock" or "Send the email". Cramming several actions into one rectangle makes the level of detail uneven and the flow hard to follow, so keep it to one task per box.
Decision (diamond): the Yes/No fork in the road
The decision is a diamond used wherever the flow splits based on a condition. Phrase the condition inside it as a question — "In stock?", "Approve?" — and always label the outgoing arrows with the outcome, such as Yes/No or Found/Not found.
Here is the thing: unlabeled branches are the single most common reason a flowchart fails to communicate. The author knows which way is Yes, but the reader has to guess. Get this one detail right and your diagram becomes far clearer.
Minami
Process improvement lead
I'll admit it — I kept skipping the labels after a diamond. Are they really that important?
Spark
DrillSpark consultant
That's the make-or-break detail! A diagram missing its Yes/No labels stops the reader cold somewhere, every time. Just adding the labels cuts down on rework, so this is the one place not to cut corners.
Flow line (arrow): the order of the steps
The flow line is the solid arrow that connects symbols to show the order of steps. As a rule, run it one way — top to bottom, or left to right — and only use an upward arrow when something genuinely has to loop back, such as a rework or rejection loop. The golden rule is to avoid crossing lines wherever you can.
These four symbols alone can capture most everyday work. Try drawing a task you know well using just these four. As you go, telling the symbols apart becomes second nature. The more complex shapes can wait until later.
Three Symbols for Data, Documents and Setup
After the four essentials, the next most common symbols are the ones that show data and documents moving around. They shine in system design and back-office process flows.
Data (parallelogram): input and output
The data symbol is a parallelogram that represents information going in or out: "Enter the customer details", "Output the summary". Use it when you want to distinguish the movement of data from the process (the work itself). It is especially important in program flowcharts.
Document (wavy base): forms and document output
The document symbol is a rectangle with a wavy bottom edge, representing a paper form or a document such as a PDF. When the deliverable takes the form of a document — "Issue the invoice", "Submit the report" — using this symbol instead of the data symbol conveys your intent more precisely.
Preparation (hexagon): setup and groundwork
The preparation symbol is a hexagon for setup done before the main work. In a program that might be initializing a variable, such as "Set the counter to zero"; in a business process it might be groundwork like "Set up the venue". You won't use it often, but it is handy for making the setup before a loop explicit.
Spark
DrillSpark consultant
If you're ever unsure which shape is which, check the shape name in your tool. In Excel and PowerPoint these all live under the "Flowchart" category, so the label tells you exactly what you're placing.
Three Advanced Symbols: Predefined Process, Loop and Connector
When a flowchart starts to grow large and complex, these three symbols help you tidy it up. Each one exists to split a diagram apart so it stays readable.
Predefined process (double side bars): steps split into another diagram
The predefined process is a rectangle with double vertical bars on each side, meaning "the details are defined in a separate flowchart". For example, you can pull the "credit check" out of an order flow into its own diagram and represent it in the main flow with this single symbol, keeping the big picture clear.
Loop limit: the range of a repeated block
The loop limit is a pair of symbols that bracket the start and end of a repeated block. Write the repeat condition on the opening symbol — something like "Repeat for every order" — and the closing symbol shows where it ends. You can also express a loop with a decision and a backward arrow, but when the repeated range is long, the loop limit reads more clearly.
Connector (small circle): linking distant points
The connector is a small circle for cases where drawing a direct flow line would create a tangle of crossings, or where the diagram spans several pages. Two connectors carrying the same letter — A, B and so on — are understood to be joined, passing the flow from one to the other. Overuse them and the diagram gets harder to follow, so keep it to a few per page.
What these three share is one idea: don't cram everything onto a single page. Once you pass roughly 20 process boxes, take it as a sign to split the diagram using predefined processes and connectors.
How to Draw with the Symbols: 3 Rules and Worked Examples
Once you know what the symbols mean, the next step is combining them. Readable flowcharts tend to follow three shared rules.
- Keep the flow in one direction: run it top to bottom (or left to right), and reserve backward arrows for exceptions such as rework loops.
- One symbol, one idea: write a single task in each process rectangle and keep the level of detail consistent.
- Always label branches: spell out the outcome (Yes/No and so on) on every arrow leaving a decision symbol.
Beyond the three rules, pay attention to the wording inside each symbol. End a process with a verb ("...the stock") and phrase a decision as a question ("...?"). When the language is consistent too, not just the shapes, you take a real load off the reader.
Example: an invoicing flowchart
As a real example combining the symbols above, here is an invoicing flow. The terminator, process, decision, data and predefined process each appear in their own role.
The rounded rectangles are the start and end, the parallelogram is data input, the double-barred rectangle is a predefined process (the credit check is detailed in a separate diagram), and the diamond is the branch. Just by choosing the right symbols, the nature of each step comes through without any prose — that is the real strength of a flowchart.
Spark
DrillSpark consultant
Whether a diagram is good comes down to one test: can you tell each step's role from its shape alone? Before you add color or decoration, get the symbols right. Once they line up, the reader's job gets easier on its own.
Example: a flowchart with a decision and a loop
Here is one more: an inspection process that "repeats until it passes". A backward arrow from the decision symbol expresses the redo loop.
3 Common Flowchart Symbol Mistakes
Even when you know what the symbols mean, one wrong move in how you use them and the diagram stops communicating. The good news is that the stumbling points are fairly predictable. Here are three mistakes beginners often make, each paired with a fix. Know them in advance and you can sidestep the same traps.
Mistake 1: confusing process and decision
This is drawing "Check the stock" as a diamond (decision). The act of checking is a process (rectangle); the branch based on its result, "In stock?", is the decision (diamond). Separate the action from the branch and the flow becomes far easier to follow.
Mistake 2: leaving out the start and end terminators
A flowchart without terminators leaves the reader unsure where to start reading and where it ends. This matters especially in documents where people jump between diagrams — the entry and exit must be explicit. No matter how small the diagram, always place a start and end terminator.
Mistake 3: using custom or Excel shapes for no reason
Decorative clouds, stars and other non-standard shapes make the reader wonder, "Does this shape mean something special?" Instead of adding shape variety, stick to the standard symbols and use color or bold to highlight what matters.
Once You Know the Symbols, Let a Tool Speed Up the Drawing
Once you understand what the symbols mean and how to use them, all that's left is to draw. And yet this is exactly where many people hit a new wall.
Placing shapes one by one in Excel or PowerPoint eats up time on alignment and re-routing arrows. Fix one spot and the layout shifts, so you burn the rest of the day on cleanup — sound familiar? It would be a shame to learn the symbols and then get worn out by the drawing itself.
That's where DrillSpark comes in. Just describe your process in plain language, and AI drafts the flowchart in about 30 seconds. The tool handles symbol choice and layout automatically, so you can focus on the substance of the flow.
You can try the AI drafting on the free plan. Use it to double-check the symbols you learned here — pick one task you know well and turn it into a diagram.
Summary: Start by Mastering the 4 Basic Symbols
Key takeaways
- Flowchart symbols are a shared language defined in ISO 5807; the 10 main shapes are enough for real work.
- Learn the four basics first: terminator, process, decision and flow line.
- Symbols like data, document and predefined process let you express your intent more precisely.
- The three big mistakes: confusing process and decision, omitting terminators, and inventing custom shapes.
You don't have to memorize every symbol at once. Draw a small flowchart with the four basics, then come back to the table in this article whenever you need the rest. That habit is the one that actually sticks.
And a procedure that only lives in your head reveals its waste and gaps the moment you draw it out. What matters isn't picking the perfect symbol — it's drawing that first diagram and making the work visible.
When you're staring at a blank page and can't get started, let DrillSpark help. Just describe the task you want to map in plain language, and AI drafts the flowchart in about 30 seconds. Symbols and layout are arranged for you, so all that's left is to refine the parts that catch your eye, in conversation.
No credit card required — it's free to start. Begin with one task you know well: describe it to DrillSpark and watch it become a diagram.
Minami
Process improvement lead
The symbols finally clicked for me. I think I can draw straight into tomorrow's handover doc!
Spark
DrillSpark consultant
That's the spirit! Draw one with the four basics first. Whenever you're unsure, just come back to this table. I'm cheering on your "let's give it a try" all the way.