Flowchart

What Is a Flowchart

A flowchart is a diagram that represents a process or workflow using standardized shapes connected by arrows to show the sequence of steps, decision points, and directional flow from start to finish. Each shape has a specific meaning: rectangles represent actions, diamonds represent decisions, ovals represent start and end points, and arrows show the direction of flow.

Flowcharts have been used in business and engineering since the 1920s when Frank and Lillian Gilbreth introduced the flow process chart to the American Society of Mechanical Engineers. The standardized symbol set used today was formalized by the American National Standards Institute (ANSI) in the 1970s and later adopted as ISO 5807.

The enduring popularity of flowcharts comes from their simplicity. Unlike text based process documentation that requires reading and interpretation, a flowchart communicates process structure visually. A well designed flowchart can be understood in minutes by anyone, regardless of their familiarity with the process, which makes it one of the most accessible tools for process communication.

Standard Flowchart Symbols

Flowcharts use a standardized set of shapes defined by ANSI and ISO. Using these symbols correctly ensures your flowcharts are readable by anyone familiar with the convention.

In practice, most business flowcharts use only four of these symbols: ovals for start and end, rectangles for actions, diamonds for decisions, and arrows for flow. The additional symbols (data, document, connector) appear in more detailed technical or systems flowcharts.

Types of Flowcharts

Different flowchart types serve different analysis and communication purposes. The right type depends on what you are trying to show and who the audience is.

Basic Flowcharts

A simple linear or branching sequence of steps showing how a process flows from start to finish. Basic flowcharts use only the core symbols (oval, rectangle, diamond, arrow) and work best for straightforward processes with limited branching. They are the most common type used in everyday business documentation.

Swimlane Flowcharts

A flowchart divided into horizontal or vertical lanes, with each lane representing a different role, department, or system. The process steps are placed in the lane of the person or team responsible for them. Swimlane flowcharts are essential for cross functional processes because they make responsibility and handoffs explicit. They answer not only “what happens” but “who does it” at every step.

Data Flow Diagrams

A specialized flowchart that focuses on how data moves through a system rather than how work is performed. Data flow diagrams show data sources, processes that transform data, data stores, and destinations. They are used in software engineering and systems analysis, not general business process documentation.

Workflow Diagrams

A flowchart that includes additional context about each step, such as time estimates, tools used, or approval requirements. Workflow diagrams bridge the gap between a simple flowchart (which shows sequence) and full process documentation (which includes everything). They are useful for operational planning where timing and resource information matters alongside the process flow.

Decision Flowcharts

A flowchart designed specifically to map decision logic, with a heavy emphasis on diamond (decision) shapes and branching paths. Decision flowcharts are used for complex decision processes such as loan approval criteria, insurance claim routing, customer support escalation paths, and medical triage protocols. They help ensure consistent decisions across different people following the same criteria.

When to Use a Flowchart

Flowcharts are the right tool when visual representation adds more clarity than text alone. This is typically true when the process involves sequential steps with a clear start and end, decision points that create branching paths, handoffs between roles or systems, or when the audience includes people who are not familiar with the process.

Flowcharts are particularly valuable for onboarding new employees to processes, getting stakeholder alignment on how a process should work, identifying bottlenecks and redundancies during process improvement, and documenting decision logic that needs to be applied consistently.

Flowcharts are less useful for processes that are entirely linear with no decisions (a numbered checklist works better), highly variable creative work with no standard path, or extremely complex systems with hundreds of steps (where the flowchart becomes unreadable and a written document with section headers is more navigable).

Flowchart Best Practices

Keep the diagram flowing in one primary direction: top to bottom or left to right. Mixing directions makes the flowchart harder to follow. Use consistent spacing between shapes to create visual rhythm and reduce cognitive load.

Every decision diamond should have exactly two outputs clearly labeled (typically Yes/No or True/False). Ambiguous decision outputs are the most common source of confusion in flowcharts. If a decision has more than two possible outcomes, break it into multiple sequential decisions.

Limit each flowchart to one page or screen. If the process is too complex for a single view, break it into sub processes and use connector symbols to link between pages. A flowchart that requires scrolling or page turning loses its primary advantage of providing an at a glance overview.

Use consistent, descriptive text inside shapes. Start action steps with verbs: “Review application,” “Calculate total,” “Send notification.” Keep text concise but specific enough that the reader understands what the step involves without additional context.

Include a title, date, version number, and author on every flowchart. Without version control, teams end up working from different versions of the same process diagram, which defeats the purpose of visual documentation.