UML - Component Diagram Tutorial

UML component diagram tutorial

Component diagrams are a time-tested way to depict the wiring of components in a system, especially a software system. This UML component diagram tutorial can help software engineers, CS students, and others use UML to create component diagrams.

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Like other UML diagrams, component diagrams can be confusing at first glance. That's why it's crucial to pick an easy-to-learn UML tool that gets out of your way. Simple UML diagrams can be sketched out with pen and paper or a whiteboard, but you'll want to use a computer program for more complex creations.

We'll proceed as though you're using Lucidchart. Our program allows you to pick up and play with no training, and collaborating with clients or colleagues is an enjoyable process with our real-time collaboration.

UML component diagram tutorial
UML component diagram tutorial
UML component diagram tutorial



Create a new document in Lucidchart and click "More Shapes" to turn certain shape libraries on or off. Select the UML shape library to display, then find the UML component diagram symbols. In Lucidchart, you can simply click and drag shapes from the toolbox to the canvas, then repeat that action to adjust their position.

Start by dragging the component shape onto the canvas, then label it with the correct name. If the shape does not include a stereotype classifier—a small image of a component diagram—remember to type “component” inside double angle brackets. That's because UML 2.0 interprets a rectangle without any stereotype classifier as a class element.

UML component diagram tutorial


Add a component for each main functional unit in your application or system. The more you can separate each component, the easier it will be to read and update in the future. Remember that you can group components in a package shape, or even within a larger component shape if you're representing internal components within a larger one.

UML component diagram tutorial



Model a component's interfaces with textual details or symbols. By definition, a component provides one or more public interfaces. These interfaces show what a component either receives or provides, such as input from another component or services to an end user.

In UML, you can list provided and required interfaces in an additional compartment within a component shape. You can also model these details with lollipop and socket symbols, which represent provided interfaces and required interfaces, respectively. Note that using the latter option requires dependency arrows, just as with class and deployment diagrams. A dependency is signified by a dashed line that ends in an arrow, which indicates that one node or component is dependent on another.


Components may also include ports, which specify a separate interaction point between the component and the environment. Ports are represented as small squares on the side of a component shape. To label your ports, just drag out a text shape and start typing. Components and their ports can be wired together with dependencies and additional interface information, if needed.


Finish up your diagram by adding any nodes that are represented in your system. Nodes are computational resources, such as computers, printers, or servers, that are used by UML artifacts to execute commands or processes. In Lucidchart, nodes are modeled with boxes that appear to be three-dimensional.



Before you share your component diagram, take it to a trusted mentor or co-worker and ask for their feedback. They may be able to spot inappropriate connections or hardware misuse and help you correct the diagram. Then take a final look at the document before you publish. Your component diagram is now ready for use in any business or engineering setting!

Lucidchart's features are constantly evolving to keep pace with industry standards. To see which UML shapes are currently offered, sign up for free and explore the product.

UML component diagram tutorial

Lucidchart can help you create UML diagrams for work or school. Our cloud-based software works on any platform, so users can access Lucidchart anywhere, any time. Try it and see for yourself!

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