Iso 5807 Standard Flowchart Symbols Quick Reference Guide

If you've ever looked at a flowchart and wondered what a particular symbol means or why your colleague's flowchart looks nothing like yours you already understand why a shared standard matters. The ISO 5807 standard flowchart symbol reference gives everyone using flowcharts a common visual language. Without it, process diagrams become guesswork. With it, anyone on your team can read, interpret, and build flowcharts that actually communicate.

What Is the ISO 5807 Standard?

ISO 5807 is an international standard published by the International Organization for Standardization. Its full title is "Information processing Documentation symbols and conventions for data, program and system flowcharts, program network charts and system resources charts." It was first introduced in 1985 and defines a set of standardized symbols, rules, and conventions for creating flowcharts used in information processing and systems documentation.

The standard covers how to represent processes, decisions, data flows, and connectors in a way that removes ambiguity. When someone in Tokyo draws a flowchart, a developer in Berlin should be able to read it without needing a legend written in the margins.

You can review the official ISO 5807 standard on the ISO website for the full technical specification.

Why Do Flowchart Symbols Need a Standard?

Flowcharts are used everywhere in software development, manufacturing, business process mapping, and quality management. But without a standard, each team might use different shapes to mean the same thing. A diamond might mean "decision" to one team and "external input" to another.

This causes real problems:

New team members struggle to read existing documentation
Cross-team collaboration slows down because diagrams need translation
Auditors and regulators can't verify processes if symbols are inconsistent
Automated tools can't parse non-standard flowcharts correctly

A standard like ISO 5807 fixes this by assigning each flowchart symbol shape a specific meaning, so the shape itself carries the information no extra explanation needed.

What Are the Core Symbols Defined in ISO 5807?

ISO 5807 defines a set of symbols grouped by function. Here are the main ones most people encounter:

Process symbol (rectangle) Represents a single step or operation in a process. This is the most commonly used symbol in any flowchart.
Decision symbol (diamond) Indicates a point where a yes/no or true/false question determines the next step.
Terminal symbol (rounded rectangle or oval) Marks the start or end point of a flowchart.
Input/Output symbol (parallelogram) Shows where data enters or leaves the process.
Flowline (arrow) Connects symbols and shows the direction of process flow.
Connector symbol (small circle) Used to link parts of a flowchart that span across pages or to avoid crossing lines. You can read more about how the connector symbol works in complex diagrams.
Predefined process symbol (double-bordered rectangle) Refers to a process defined elsewhere, like a subroutine or a separate flowchart.
Document symbol (rectangle with a wavy bottom edge) Represents a printed document or report produced during the process.
Storage symbol (inverted triangle) Indicates data stored in a file or database.
Manual operation symbol (trapezoid) Denotes a step performed manually rather than by a system.

For a more detailed breakdown of each shape and when to use it, see this ISO 5807 symbol reference guide.

How Are ISO 5807 Symbols Different from Other Flowchart Standards?

Several flowchart standards exist, and this is where confusion often starts. Here's how ISO 5807 compares:

ISO 5807 vs. ANSI/ISO standard symbols Many U.S. organizations follow ANSI (American National Standards Institute) symbols, which overlap significantly with ISO 5807 but have subtle differences in how certain symbols are drawn.
ISO 5807 vs. BPMN Business Process Model and Notation (BPMN) is a newer standard designed specifically for business process modeling. BPMN uses different shapes and includes swimlanes, message flows, and event markers that ISO 5807 doesn't cover.
ISO 5807 vs. UML diagrams Unified Modeling Language is used in software engineering for object-oriented design. UML activity diagrams look similar to flowcharts but follow different conventions.

ISO 5807 is most useful for traditional data processing and system flowcharts. If your work involves business process management at an enterprise level, BPMN might serve you better. For software architecture, UML is usually the right choice. But for general-purpose technical flowcharts especially in documentation, QA, and IT process mapping ISO 5807 remains a reliable reference.

When Should You Use ISO 5807 Symbols?

Use ISO 5807 symbols when you need flowcharts that are:

Formally documented Regulatory filings, audit trails, and compliance documentation often require standardized notation.
Shared across teams or organizations When people outside your immediate team will read your diagrams, a standard prevents misinterpretation.
Used in training materials New employees learn faster when diagrams follow a consistent, recognized format.
Part of a quality management system Standards like ISO 9001 expect clear, standardized process documentation.

If you're sketching a quick process on a whiteboard for your own team, strict ISO compliance isn't necessary. But the moment your flowchart becomes a deliverable or a document of record, using recognized symbols makes a real difference.

What Common Mistakes Do People Make with ISO 5807 Symbols?

Even experienced professionals slip up with flowchart symbols. Here are the most frequent errors:

Using a rectangle for decisions instead of a diamond. This is the single most common mistake. A decision point always needs a diamond shape with two or more exit paths.
Mixing symbol conventions from different standards. Combining ISO 5807 symbols with BPMN or UML elements in the same diagram creates confusion.
Omitting start and end terminals. Every flowchart needs a clear entry and exit point. Skipping these makes diagrams hard to follow.
Overusing connectors. Connectors are useful for large diagrams, but overusing them where a simple flowline would work creates unnecessary visual clutter.
Not labeling decision branches. A diamond with unlabeled exits forces the reader to guess what each path means. Always label branches with the condition (yes/no, true/false, or specific values).
Inconsistent symbol sizing. While ISO 5807 doesn't enforce strict sizes, keeping symbols roughly the same size makes diagrams cleaner and more professional.

How Can You Start Using ISO 5807 Symbols Correctly?

You don't need to memorize every symbol in the standard to get started. Here's a practical approach:

Learn the five core symbols first. Process (rectangle), decision (diamond), terminal (rounded rectangle), input/output (parallelogram), and flowline (arrow). These cover about 90% of what you'll need.
Use a flowchart tool that supports ISO symbols. Tools like Microsoft Visio, Lucidchart, draw.io, and SmartDraw all include ISO-compliant symbol libraries.
Add a legend to your flowcharts. If your audience isn't familiar with ISO 5807, a small legend in the corner of your diagram prevents confusion.
Review existing flowcharts against the standard. Pick one process diagram from your documentation and check it symbol by symbol against ISO 5807. You'll likely find two or three symbols to fix.
Keep the full reference accessible. Bookmark the detailed ISO 5807 symbol reference so your team can look up any symbol quickly.

Quick Checklist for ISO 5807-Compliant Flowcharts

Use this checklist before finalizing any flowchart that follows ISO 5807:

☐ Every flowchart has a clearly marked start and end terminal
☐ Decision points use diamond shapes with labeled branches
☐ Process steps use rectangles not circles, not hexagons
☐ Data input/output uses parallelograms, not rectangles
☐ Flowlines show direction with arrows and don't cross without a clear junction
☐ Connectors (small circles) are used to avoid tangled lines across pages
☐ A legend is included if your audience may not know ISO 5807
☐ Symbols from other standards (BPMN, UML) are not mixed in
☐ Each symbol is large enough to read and roughly consistent in size
☐ The flowchart reads top-to-bottom or left-to-right without backtracking

Print this checklist and keep it next to your desk. The next time you build a flowchart, run through it before sharing the diagram. Five minutes of checking now saves hours of confusion later.