UML Class Diagram Tool

Visualize and Create Effective Designs

Create a high-level view of a system's design to model, plan and document the architecture.

  • Design UML class diagrams to design and document systems easily.
  • Simple drag and drop interface to visualize how a system interacts.
  • Real-time collaboration and multi-cursor support for effective team collaboration
Visualize and Create Effective Designs

Class Diagram Templates

Class Diagram for Bank ATM System

Class Diagram for Bank ATM System

Class Diagram for Taxi Service

Class Diagram for Taxi Service

Class Diagram for Recommendation System

Class Diagram for Recommendation System

Unity Class Diagram

Unity Class Diagram

Online Job Portal Class Diagram

Online Job Portal Class Diagram

Social Media Class Diagram

Social Media Class Diagram

What is a Class Diagram?

A class diagram is a static UML diagram type that describes the structure of a system by showing its classes, attributes, operations, and relationships among objects.

Class diagrams are used for visualizing, describing, and documenting different aspects of a system so that you can construct executable code for software applications.

Class diagram Symbols and Notaions

  1. UML Class Notation

    • Name: the first partition is to include the name of the class.
    • Attributes: the second partition will include the attributes followed by the attribute type.
    • Operations: the third partition is dedicated to operations, which shows the services the class provides.
  2. Class Visibility

    • Public attributes or operations: +
    • Private attributes or operations: -
    • Protected attributes or operations: #
  3. Relationships Between Classes

See our guide to UML Class Diagram Relationships Explained with Examples to learn in detail about the relationships between classes.

  1. Parameter Directionality

Parameter directionality shows the direction in which data is passed between objects or methods and is used to indicate whether a parameter is an input parameter, an output parameter, or both. The following are used to denote the parameter directionality.

  • In: is used to indicate that the parameter is an input parameter. This means that the parameter value is passed into the method or operation from the calling object.

  • Out: is used to indicate that the parameter is an output parameter. This means that the parameter value is returned from the method or operation to the calling object.

  • InOut: is used to indicate that the parameter is both an input and an output parameter. It means that the parameter value is passed into the method or operation from the calling object, and then updated or modified by the method, and returned back to the calling object.

How to Create a Class Diagram on Creately with Your Team?

  1. Identify the classes

As the first step, get together with your team and identify the classes that will be included in the design. Discuss and collaborate with Creately’s whiteboarding capabilities and use Microsoft Teams integrations to carry out online meetings easily.

  1. Establish relationships

Discuss and agree on the type of relationships and dependencies between classes, such as inheritance, aggregation, and association.

  1. Define the attributes and methods

Next, the team should focus on identifying the attributes and methods for each class. Discuss the responsibilities and behaviors of each class and note down important information on the canvas using sticky notes.

  1. Create the diagram

You can start creating the diagram by using Creately’s multiple class diagram templates or with a blank canvas. Add the required shapes and information using the specific UML shape library complete with class, interface, data type, and package shapes.

Simply drag and drop shapes onto the canvas to represent classes, attributes, and methods. Note composition and multiplicity relationships with specific icons. Link data, notes, and other relevant information to classes using the data panel for added context. Use shape links to connect various classes on the canvas together for easy navigation and better understanding.

  1. Finish the model with other UML diagram types

Use complementary diagrams like UML sequence diagrams, component diagrams and state machines to explain the design of the systems further. You can link these items together for even better documentation of the system.

  1. Review, refine and finalize

Once the diagram is ready, share and review it with your team. Look for any inconsistencies and accuracy issues. Provide feedback with in-line commenting and @ mentions to notify responsible parties immediately.

Make the necessary changes and once everyone is satisfied, finalize. Export the completed class diagram in multiple formats, including JPEGs, SVGs, PNGs, PDFs, and more.

Class Diagram Articles

FAQs about Class Diagram

How to draw effective class diagrams?
  1. Understanding the domain is the first step in drawing an effective class diagram. Start with the main entities first, their relationships and create them first.

  2. Get feedback on the high level design from stakeholders and compare it with the requirements. Use Creately’s real-time collaboration on a conference call to do this. Use the ‘spotlight mode’ to guide others as you talk through your thinking.

  3. Build the secondary classes, tune the relationships and add key attributes and methods to the diagram as you expand.

  4. Use the notes capability to attach explanations of each class and its role where needed.

  5. Always make sure the parent elements are higher than the child elements when drawing generalization or realization hierarchies on a diagram. Follow general conventions so that the diagram is easy to understand.

  6. Do not shy away from colors! Colorful UML Class diagrams are more helpful than monochromatic ones.

Why is Creately a better class diagram tool?
Creately is an intuitive class diagram tool that comes with standard shape libraries and templates not only for class diagrams but also for all UML diagram types. It has easy-to-use drag and drop tools and powerful collaboration capabilities that allow remote or hybrid teams to get together and work on designing systems productively. Moreover, you can migrate system data from other tools via Creately plugins and data import options and visualize them on the canvas as meaningful data shapes which you can extend with additional data fields, properties, and additional notes and by attaching links, docs, images, etc.
How to share your class diagram?
You can share your class diagrams in multiple ways using Creately’s class diagram tool. You can use a sharing link with edit or view access with collaborators or you can export the class diagram in multiple image formats including PNG, SVG, or PDF to share or publish it. Additionally, you can also use a secure embed code to embed the class diagram in any site or intranet or use workspace view mode to do a full-screen presentation.
How to collaborate with colleagues using Creately?

Creately’s class diagram tool offers many collaboration capabilities to help teams work productively together no matter where they are.

  • Real-time cursors to work with teams on a shared canvas, develop a common understanding of the systems - identify vulnerabilities and plan for future states.
  • Share feedback with pinpointed comments and discussion threads.
  • Version history to save and revert back to each iteration to streamline reviewing and revising going forward.
  • Advanced collaborator controls to streamline reviewing and revising going forward.