Best Free UML Diagram Tools & Software Best Free UML Diagram Tools & Software

The 10 Best Free UML Diagram Tools & Software

Mapping out your next project? Discover free UML tools that don’t skimp on features.

Navigating the labyrinth of Unified Modeling Language (UML) tools can be a daunting task, especially when budget constraints are in the picture. The good news? You don’t have to splurge to get your hands on a solid piece of software that can handle your diagramming needs. Our roundup is aimed at dispelling the myth that free tools lack quality, by presenting you with a curated list of UML diagram applications that offer robust features without denting your wallet.

So, what can you expect from a free UML tool? The essentials, certainly—use case diagrams, class diagrams, and sequence diagrams to name a few. But we’re also talking about user-friendly interfaces, collaboration capabilities, and export options that give some paid alternatives a run for their money. Whether you’re a seasoned developer or a student getting your feet wet, there’s something in this list for everyone.

Before we dive into the specifics, let’s clarify one thing: “free” doesn’t always mean “flimsy” or “short-lived.” Several of the tools we’re about to discuss have been around for years, benefiting from regular updates and a strong user community. Get ready to meet the UML tools that could easily become your new go-to for software design.

A web-based UML diagram tool offering a range of templates and shapes for UML diagrams. is a robust, web-based UML diagram tool that specializes in providing an array of templates and shapes specifically designed for UML diagrams. This software is highly regarded for its user-friendly interface and its ability to facilitate the creation of diagrams with ease. As a cloud-based platform, ensures that your diagrams are accessible from anywhere and can be seamlessly integrated with popular platforms like Google Drive and Dropbox.

The functionality of extends beyond just creating UML diagrams. It also serves as an effective tool for creating flowcharts, process diagrams, ER diagrams, data flow diagrams, network diagrams, and more. Its versatility makes it an ideal choice for individuals and teams who regularly work on complex projects that require clear visual representation.

Key Features

  • Extensive Library of Shapes: boasts a comprehensive library of shapes that cater to various diagram types including UML, BPMN, Flowchart, Network Diagrams among others.
  • Integration Capabilities: The software allows users to save their work directly to services like Google Drive or Dropbox ensuring accessibility from anywhere.
  • Collaboration: supports real-time collaboration enabling teams to simultaneously work on the same diagram making it ideal for team projects.

Pricing stands out among its competitors due to its pricing policy – it’s completely free! There are no premium tiers or hidden costs involved which makes it an excellent choice for students or professionals on a budget seeking a reliable UML diagramming tool.


An online UML tool with collaborative features and extensive library of shapes.

Lucidchart is a robust online diagramming tool that offers an extensive array of features to create UML diagrams efficiently. It serves as a collaborative platform where teams can work together in real-time, making it an ideal tool for brainstorming, project management, and visualization of complex systems. Lucidchart supports a wide range of diagram types including flowcharts, wireframes, and mind maps among others. With its intuitive interface and comprehensive library of shapes, it offers a seamless user experience for both beginners and professionals.

This software allows users to create professional-looking UML diagrams without the need for any design skills. It’s cloud-based nature ensures that your work is automatically saved and accessible from any device with an internet connection. Lucidchart fosters collaboration by allowing multiple users to edit diagrams simultaneously in real-time. Moreover, it integrates with popular platforms like Google Drive, Slack, Atlassian’s Jira and Confluence, enhancing its usability across different workflows.

Key Features

  • Collaborative Features: Lucidchart allows multiple users to edit the same diagram simultaneously in real-time. This feature enhances team collaboration and speeds up the process of creating complex diagrams.
  • Extensive Shape Library: Lucidchart provides an extensive library of shapes which can be easily dragged and dropped onto the canvas. This feature simplifies the creation of UML diagrams by providing all necessary elements at your fingertips.
  • Integration with Other Platforms: Lucidchart seamlessly integrates with popular platforms like Google Drive, Slack, Atlassian’s Jira and Confluence. This integration enhances its usability across different workflows by allowing users to directly import/export their work to/from these platforms.


Lucidchart offers a free version with limited features which is suitable for individual use or small projects. For more advanced features and larger teams, they offer paid plans starting at $7.95 per user per month when billed annually.


A powerful diagramming tool with real-time collaboration, templates, and many diagram types.

Creately is a robust diagramming tool that stands as a beacon in the realm of UML (Unified Modeling Language) diagram tools. It’s an online application that provides a platform for creating, editing, and sharing diagrams, making it an invaluable asset for teams and individuals seeking to visually represent complex information. Creately’s interface is intuitive and user-friendly, allowing even those with minimal technical knowledge to create professional-level diagrams with ease.

The software is not just about creating diagrams; it’s a comprehensive solution designed to facilitate real-time collaboration. This means you can work on your diagrams simultaneously with your team members, irrespective of geographical barriers. With an extensive library of templates and support for many diagram types, Creately provides the flexibility to cater to various project requirements.

Key features

  • Real-Time Collaboration: This feature allows multiple users to work on the same diagram simultaneously, making it perfect for team projects.
  • Extensive Template Library: Creately offers an array of pre-designed templates across various categories, aiding in fast and efficient diagram creation.
  • Support for Many Diagram Types: From UML to flowcharts to organizational charts, Creately supports a wide variety of diagram types.

When it comes to pricing, Creately offers both free and premium plans. The free plan allows up to 5 public diagrams with 3 collaborators per diagram. For more extensive use, they offer paid plans starting from $5 per month (when billed annually) which includes unlimited diagrams and collaborators along with priority support.

Visual Paradigm Online

VP Online
An all-in-one online UML software that supports UML, ERD and Organization Chart.

Visual Paradigm Online (VP Online) is a comprehensive online diagramming platform that caters to a wide range of professional and educational needs. It’s an all-in-one UML software that supports not only UML (Unified Modeling Language), but also ERD (Entity Relationship Diagram) and Organization Chart creation. With its robust set of features, it provides users with the tools necessary to visualize complex data and processes, making it easier to understand and communicate ideas.

The software is designed with simplicity in mind, providing an intuitive interface that makes creating diagrams a breeze. It’s accessible from any web browser, which means you can work on your diagrams wherever you are, as long as you have an internet connection. Additionally, since it’s online, it facilitates real-time collaboration between team members, making it ideal for teams working remotely.

Key features

  • Support for Multiple Diagram Types: Apart from UML diagrams, VP Online also supports ERD and Organization Charts among others. This versatility makes it a suitable tool for various applications.
  • Real-Time Collaboration: VP Online allows multiple users to work on the same diagram simultaneously. Changes made by one user are instantly visible to others.
  • Extensive Library of Templates: The software comes with a rich collection of professionally designed templates that can be used as starting points for your own diagrams.

In terms of pricing, Visual Paradigm Online offers several plans tailored to different user needs:

  • The Free Plan: Offers basic diagramming with limited storage.
  • The Standard Plan: Priced at $6 per user per month; offers unlimited diagrams and 1GB storage.
  • The Advanced Plan: Priced at $12 per user per month; offers premium features such as high-resolution export and advanced sharing options.
  • The Enterprise Plan: Custom pricing based on specific business needs; includes all features and priority support.

Each paid plan comes with a 30-day money-back guarantee, allowing you to test out the features risk-free.


A GTK+ based diagram creation program for Linux, Unix and Windows.

Dia is a GTK+ based diagram creation program that supports multiple platforms including Linux, Unix, and Windows. This open-source software is part of the GNOME project and is designed to be much like the commercial Windows program ‘Visio’. It can be used to draw different types of diagrams and provides support for UML static structure diagrams (class diagrams), entity-relationship diagrams, network diagrams, and more.

The versatility of Dia makes it an excellent choice for professionals who need a reliable tool for creating complex diagrams. With its extensive range of features, this software allows users to create high-quality diagrams in a user-friendly environment. Its cross-platform compatibility ensures that users can access the tool irrespective of their operating system.

Key Features

  • Cross-Platform Compatibility: Dia can be used on multiple platforms including Linux, Unix, and Windows. This ensures that users are not restricted by their operating system when using this software.
  • Extensive Diagram Support: Dia supports various types of diagrams including UML static structure diagrams (class diagrams), entity-relationship diagrams, network diagrams among others.
  • Customization: Dia allows users to customize their work by providing options for colors, fonts, line styles and more.


Dia is an open-source software which means it’s free to use. Users can download it from its official website or from the repository if they are using Linux as their operating system. As an open-source tool, users also have the option to modify or improve the source code as per their requirement without any additional cost.


A sophisticated software modeler aimed to support agile and concise modeling.

StarUML is an advanced software modeling tool designed to support agile and concise modeling. The platform offers a sophisticated environment for software developers, systems engineers, and other professionals who need to create and manage UML (Unified Modeling Language) diagrams. StarUML’s primary goal is to provide a software modeling platform that can be easily used while still offering powerful features.

One of the key advantages of StarUML is its focus on UML, which is a standardized general-purpose modeling language in the field of software engineering. With this focus, StarUML allows for flexible and powerful diagramming in line with the latest UML standards. It’s also an ideal tool for those who are involved in Agile development processes, where rapid iteration and simplicity are paramount.

Key Features

  • Support for Multiple Languages: StarUML supports not just UML but also other popular languages like ERD, SysML, and BPMN among others.
  • Model-Driven Development (MDD): StarUML supports MDD allowing you to generate codes from your UML diagrams in various programming languages such as Java, C++, or Python.
  • Plug-In Support: The platform has robust extensibility through plugins that can add new functionalities or enhance existing ones.


StarUML offers both a free version and paid licenses. The free version includes all basic features needed for diagramming but comes with limitations on some advanced functionalities like model-driven development or document generation.

The paid licenses start at $89 for a single user license which includes all features without any limitations plus free updates for minor versions within the purchased major version. For teams or organizations requiring multiple licenses, they offer volume discounts making it more affordable as the number of required licenses increases.

yEd Graph Editor

yEd - graph editor
A powerful desktop application that can be used to quickly and effectively generate high-quality diagrams.

yEd Graph Editor is a dynamic and robust desktop application that empowers users to swiftly and efficiently create high-quality diagrams. This powerful tool is designed to accommodate a wide range of diagramming needs, from simple flowcharts to complex network structures and hierarchical graphs. The software’s primary aim is to simplify the process of diagram creation while maintaining a high standard of versatility and functionality.

The yEd Graph Editor is built on the foundation of providing an intuitive interface for the seamless creation, editing, and customization of diagrams. It offers a broad spectrum of graph layout algorithms that enable users to automatically arrange even large data sets at the click of a button. The software’s capacity for creating visually pleasing and structured diagrams has made it a popular choice among professionals in various fields, including project management, IT, engineering, and education.

Key features

  • Automated Layout Algorithms: These algorithms allow for automatic arrangement and optimization of diagrams based on user-defined criteria such as tree layout, radial layout, or organic layout.
  • Wide Range of Diagram Types: yEd supports numerous types of diagrams such as flowcharts, network diagrams, UML diagrams, BPMN diagrams among others.
  • Import/Export Capabilities: The software supports various file formats for import/export operations including GraphML (yEd’s default format), Excel spreadsheets (.xls/.xlsx), XML files (.xml), GEDCOM files (.ged) for genealogy diagrams, etc.

As far as pricing is concerned, one of the most appealing aspects about yEd Graph Editor is that it’s completely free! Users can download the software directly from their official website without any costs attached. Despite being a free tool, it does not compromise on offering advanced capabilities or delivering high-quality results.


A component that allows to quickly write sequence diagrams, usecase diagrams, class diagrams, activity diagrams, component diagrams etc.

PlantUML is a versatile tool that serves as an integral component in the creation of UML diagrams. It offers a unique approach to diagramming, where users can quickly write sequence diagrams, use case diagrams, class diagrams, activity diagrams, component diagrams and more. This lightweight tool is designed to simplify the process of creating complex UML diagrams by providing a text-based language that is easy to understand and use.

The tool’s primary focus is on user accessibility and convenience. PlantUML eliminates the need for manual drawing and allows users to create intricate UML diagrams using simple textual descriptions. This approach not only speeds up the diagramming process but also ensures accuracy and consistency in your designs.

Key Features

  • Text-Based Diagramming: Unlike traditional UML tools that rely on drag-and-drop interfaces, PlantUML uses a text-based language for creating diagrams. This feature enables users to define their models in a descriptive manner which can be easily understood by anyone reading it.
  • Wide Range of Diagram Types: PlantUML supports an extensive list of UML diagram types including sequence, use case, class, activity, component among others. This diversity allows you to choose the most appropriate type of diagram for your specific needs.
  • Integration Capabilities: PlantUML can be seamlessly integrated with various popular IDEs like Visual Studio Code, IntelliJ IDEA and others. This integration feature enhances productivity by allowing you to create and edit your UML diagrams within your preferred development environment.


PlantUML is an open-source tool which means it is free to use for both personal and commercial purposes. Users are encouraged to contribute towards its development through donations but this is purely voluntary.


An open source modeling environment tool providing support for the latest standards (UML 2, BPMN 2, etc.)

Modelio stands as a robust open-source modeling environment tool, designed to accommodate the latest standards such as UML 2 and BPMN 2. This software offers a comprehensive platform for developers, analysts, and designers to create, analyze, and manage complex software designs. With its extensive support for UML (Unified Modeling Language) and BPMN (Business Process Model and Notation), Modelio provides a seamless experience in capturing requirements, designing software architecture, and documenting business processes.

The strength of Modelio lies in its ability to integrate system modeling with enterprise architecture and business process modeling. This integration allows users to have a holistic view of their project from different perspectives: from high-level business processes to low-level system components. Its open-source nature makes it an attractive option for organizations that require flexibility and control over their tools.

Key Features

  • Comprehensive UML Support: Modelio supports all types of UML diagrams including class diagrams, sequence diagrams, use case diagrams among others. It also supports the latest version of UML which is UML 2.
  • BPMN Support: Business Process Model and Notation (BPMN) is a standard for business process modeling. Modelio fully supports this standard allowing users to model business processes within their system design.
  • Open Source: As an open-source tool, Modelio provides the flexibility for customization according to user needs. Users can modify the source code or add plugins to enhance its functionality.


Modelio is available in two editions: the free edition which includes basic features suitable for individual users or small teams; and the professional edition which offers advanced features like team collaboration, model comparison, java code generation etc., ideal for large teams or enterprise use. The professional edition pricing is available upon request from the vendor’s website.


An industrial-grade open source Model-Based Engineering (MBE) product supporting UML and SysML with full standards compliance.

Papyrus is an industrial-grade open source Model-Based Engineering (MBE) product that supports Unified Modeling Language (UML) and Systems Modeling Language (SysML). As a tool, Papyrus provides an integrated and user-friendly environment for editing, managing, and analyzing modeling projects. It is designed to support the needs of modelers who require a high degree of control over their modeling environment while also maintaining compliance with industry standards.

Papyrus is fundamentally about enabling the creation, editing, and management of model-based designs in a way that is compliant with UML and SysML standards. These standards are widely recognized in the field of software engineering and systems engineering respectively. They provide a standardized way to visualize the design of a system. In essence, Papyrus serves as a platform for creating these visualizations in an efficient and compliant manner.

Key features

  • Standards Compliance: Papyrus supports both UML 2.x and SysML 1.x out of the box, ensuring that your models adhere to widely accepted industry standards.
  • Extensibility: As an open-source tool, Papyrus provides a high degree of extensibility. Developers can extend its functionality through plugins or even modify its source code to suit their specific needs.
  • Model Analysis: Beyond just creating models, Papyrus also provides tools for analyzing them. This includes capabilities such as model comparison, impact analysis, and traceability.

As an open-source software product, Papyrus can be downloaded and used free of charge. There are no licensing fees or subscriptions associated with using it. However, it’s important to note that while the software itself is free, getting the most out of it may require investment in terms of learning how to use it effectively or potentially customizing it to better suit your specific needs.


As we wrap up, it’s clear that free doesn’t have to equate to inferior when it comes to UML diagramming tools. Whether you’re in need of basic functionalities or a range of advanced features for team collaboration, there’s a tool on this list that should fit the bill. What’s important is to pinpoint what you actually require for your project and then align those needs with the offerings of these free solutions. Don’t underestimate the potential of community support and regular updates; they can make a world of difference in your workflow.

Choosing the right UML tool is more than just a checkbox in your software development process; it’s an investment in efficiency and clarity for your projects. We hope this roundup has helped illuminate the landscape of free UML tools, providing you with options that are both practical and budget-friendly. After all, a well-chosen tool can be the catalyst for turning a good project into a great one.