Free Class Diagram Generator Online
Free Class Diagram Generator Online
Design object-oriented structures with classes, interfaces, inheritance, and associations.
What is a Class Diagram?
A class diagram is a UML diagram that shows the structure of a system by depicting classes, their attributes, methods, and the relationships between them. It's a fundamental tool for object-oriented design, helping developers plan code architecture before implementation.
Common Use Cases
- •Software design - Plan class hierarchies and relationships
- •Database modeling - Map entities to object models
- •API design - Define data transfer objects and services
- •Documentation - Communicate system architecture to teams
- •Code generation - Use diagrams as blueprints for implementation
Syntax Quick Reference
| Element | Syntax | Description |
|---|---|---|
| Class | class Name { } | Define a class |
| Attribute | +String name | Class property (+ public, - private) |
| Method | +method() | Class function |
| Inheritance | <|-- | Extends relationship |
| Composition | *-- | Contains relationship |
| Association | --> | Uses relationship |
Export Options
PNG Export
High-resolution images for documents and presentations.
SVG Export
Scalable vectors for web and further editing.
PDF Export
Print-ready format for professional documentation.
Got Mermaid code from ChatGPT? Paste it here to render and export instantly.
Get the Free Mermaid Syntax Cheat Sheet
Free Mermaid Syntax Cheat Sheet
All 21 diagram types in one PDF reference.
Frequently Asked Questions
Ready to create your own class diagram?
Open the editor with this example pre-loaded and start customizing.
Related Diagram Types
ER Diagram Maker
Design database schemas with entities, attributes, and relationships. Import SQL CREATE TABLE statements to auto-generate diagrams, or write Mermaid ER syntax directly.
Sequence Diagram Maker
Visualize system interactions, API calls, and message flows between components.
Flowchart Maker
Design process flows, decision trees, and workflows with our intuitive flowchart editor.