What Is a Flowchart? Types, Symbols, and When to Use One

A flowchart is a diagram that maps the steps of a process using standardized shapes connected by arrows. Each shape has a specific meaning: rectangles represent actions, diamonds represent decisions, ovals mark the start and end. The arrows show the direction of flow — what happens next, and under what conditions.

Flowcharts have been used in engineering and business for over a century, standardized by Frank Gilbreth in the 1920s and formalized by the American National Standards Institute (ANSI) in 1970. They remain one of the most widely used process documentation tools because they communicate a great deal of information in a compact visual format.

This guide covers the main types, the standard symbol vocabulary, when flowcharts are the right tool, and where they fall short for operational use.

The standard flowchart symbol vocabulary

ANSI/ISO standard flowcharts use a defined set of shapes. Most business flowcharts use a subset of these:

In practice, most business teams use only four symbols: terminal, process, decision, and flow line. The rest are used in technical process documentation and data flow diagrams.

The main types of flowcharts

1. Process flowchart

The simplest type — maps the sequence of steps in a process without specifying who performs each step. Best for understanding or communicating the overall structure of a process. Commonly used in SOPs, training materials, and process improvement workshops.

2. Swim-lane diagram (cross-functional flowchart)

Adds horizontal or vertical "lanes" that represent different people, teams, or systems. Each step is placed in the lane of its responsible party. Swim-lane diagrams are the most useful format for processes that involve multiple handoffs — they make the ownership of each step, and the moments of transfer, immediately visible.

Example: an invoice approval process with lanes for AP Clerk, Department Manager, VP Finance, and Accounts Payable System. Each lane shows only the steps that person or system performs, and the arrows between lanes show the handoffs.

3. Data flow diagram (DFD)

Shows how data moves through a system — the inputs, the transformations applied, and the outputs. Used primarily in software engineering and systems design rather than for operational process documentation. If your goal is to document how information moves through a business system, a DFD is the right format.

4. Workflow diagram

A generalized term for any visual representation of a business process that includes the sequence of tasks, the decision points, and the responsible parties. Workflow diagrams are less formally defined than ANSI flowcharts — they prioritize clarity for a business audience over technical precision. A visual flow builder typically produces workflow diagrams in this sense.

When flowcharts are the right tool

Flowcharts are well suited for:

• Process discovery: Running a whiteboard session with a team to map out how a process actually works. The visual format allows everyone to see the whole picture and identify missing steps or undocumented branches.
• Stakeholder communication: Showing a client, executive, or auditor how a process works. A one-page swim-lane diagram communicates complexity more efficiently than several pages of written procedure.
• Compliance documentation: ISO, SOC 2, and other audit frameworks require documented process evidence. Flowcharts provide clear, auditable records of how processes are designed to work.
• Training and onboarding: New hires benefit from seeing the overall shape of a process before learning the individual steps. A flowchart provides the mental model; the detailed procedure fills in the specifics.

Where flowcharts fall short

Flowcharts are designed to be read, not navigated. This creates a fundamental limitation for operational use:

• A support agent cannot navigate a flowchart during a live call without losing track of where they are in the diagram
• A new hire cannot follow a flowchart on their first day without constant back-and-forth between the diagram and the detailed procedure
• A complex flowchart with many branches becomes impossible to follow when printed on a single page — and nobody follows a diagram that requires zooming and scrolling

For operational use — executing a process in real time — interactive flow tools are more effective. Instead of showing the entire diagram, they present one step at a time, ask questions at decision points, and automatically route to the next relevant step. The decision tree software and interactive workflow category addresses this gap directly.

For more on the distinction, see our guide on visual workflows and why pictures beat paragraphs for process documentation.

Flowchart best practices

• Keep it on one page if possible. A diagram that requires scrolling is a diagram that does not get used. If your process is too complex for one page, consider whether it needs to be decomposed into sub-processes.
• Flow consistently left-to-right or top-to-bottom. Do not mix orientations within a single diagram.
• Label every decision branch. Every diamond should have clearly labeled "Yes" and "No" (or equivalent) branches. Unlabeled branches create ambiguity.
• Have exactly one start and one end (or multiple clearly labeled ends). Multiple unlabeled entry points confuse readers about where the process begins.
• Validate with people who actually do the work. Process owners are often surprised by what the flowchart reveals — steps that are missing, branches that go nowhere, and decision criteria that have never been explicitly defined.

Related articles in this series

• 10 Flowchart Examples for Business Teams
• Process Mapping: How to Document Any Business Process Visually
• Visual Workflow: Why Pictures Beat Paragraphs for Process Documentation