Diagram Software

The Best 8 Free and Open Source Diagram Software Solutions

The Best 8 Free and Open Source Diagram Software Solutions

Do you want to mold your ideas and imaginations in pictorial forms? If you are willing to shape your thoughts creatively, then choosing a diagramming tool is the best option for you. In your businesses, well structured and visually appealing diagrams will help you make your complex ideas understandable.

“I think by drawing, so I’ll draw or diagram everything from a piece of furniture to a stage gesture. I understand things best when they’re in graphics, not words”. By Robert Wilson

The diagram app is quite helpful and valuable. You can build and visually shape your ideas to the audience by employing intuitive diagramming tools. The users can make beautiful diagrams from scratch with the help of diagram software technique. 

What is diagram software?

The diagram software allows users to create flow charts, floor plans, organization charts, network diagrams, engineering designs, and other types of pictures. The users enjoy the illustrative representation of data and information with diagramming tools.

 What are the characteristics of the Diagramming tool?

characteristics of diagramming tool

When to use diagram software? 

The diagramming tool can be used in various situations:

when to use diagramming tool

How is diagram software helpful?

How is diagram software helpful

What are the types of Diagram Software?  

The diagram software can be categorized in the following main categories:

categories of diagram software

Interestingly, you may come across a variety of diagram software solutions. If you want to explore the free and open source diagram tool, then have a look at the following sections of this article to understand the same.

The open source diagramming tool will allow you to customize as the source code is available for you to work. In case you are into a small business, then free diagram software will be apt for you. 

Let’s see free and open source diagramming software in detail: Before that let's have a quick glance at a comparison chart of free and open source diagram software.

Comparison Chart of Best 8 Free and Open Source Diagram Software 

comparison chart of diagram software

Free and Open Source Diagram Software 

1 Dia Diagram Editor (free and open-source)

Dia is an open source online diagramming tool designed to help users create structured diagrams. Upon installing this software, the users can create charts for any purpose. It is a free diagram editor for Windows, Mac OS X, and Linux.

Both tech-savvy and non-tech users will find the interface of this app easy-to-use. It allows you to design flowcharts, circuit diagrams, database models, and network designs. There are entity-relationship models in this tool that helps in drawing unified modeling language diagrams, network diagrams, flowcharts, and simple electrical circuits.

Interestingly, you can save and load diagrams in PNG, SVG, XFIG, and WMG. It can be used to design more than 30 diagram types. Both beginners and developers will find this tool apt. If you are a beginner, then the software allows you to draw diagrams by using more than a thousand predefined objects and symbols.  While the developers use this software as a computer-aided software engineering tool.


(Source: Dia Diagram Editor)


  • Predefined symbols and objects
  • Multiple import and export formats
  • Python Scriptability
  • User-friendly interface
  • Flowchart
  • Organizational Charting
  • Predefined objects and symbols
  • Make code skeletons from drawings

2 bpm’online studio free (free)

bpm’online studio free is the free online diagram software & visual solution that will accelerate the process design. This tool is the product by bpm’online. In a unified environment, you can design process diagrams with simple visual tools. The app standardizes process management.

You will find this tool convincing for simplified and collaborative process design. The software is free for unlimited users. The team jointly designs processes and helps to simplify the process documentation.

bpm'online free software

(Source: bpm'online studio free)


  • Flowchart
  • Organizational charting
  • Data Import and Export
  • Drag and drop
  • Mind Map
  • Templates
  • Collaboration
  • Unified CRM platform
  • Process Design

3 Lucidchart (free, single-user)

If you are looking for a powerful diagramming tool, then Lucidchart will serve your purpose. This is free diagram software solution  for a single user. It will allow the user to visualize processes and models.

The software allows multiple users to share the documents and work on them simultaneously and effortlessly. The whole team can think visually and helps in increasing productivity. 

Drawing flowcharts, org charts, UML, mind maps, and wireframes are much easier with this software. The intuitive system of this tool will help users in the field of web designing, web development, and engineering. You will find this system reliable and easy-to-use.

lucid cart software

(Source: Lucidchart)


  • Real-time and constant collaboration
  • Automated diagramming
  • Enhanced Security
  • Seamless Integrations
  • Easy Visio import/export
  • Secure team management
  • Preset shape libraries
  • Drag and drop
  • Google Docs Integration and Google single sign-on

4 Creately (free and cloud-hosted)

Creately is a cloud-hosted app and is free for 5 public documents. The other plans of this software come with a 30-day money-back guarantee. It offers the simplest way to visualize plans, processes, ideas, and concepts. Even when you are offline, you can access diagrams with this tool. You can convert your thoughts into visuals with this app.

You can gain the desired size by clicking on the shape and dragging it across the screen as this tool offers ease of diagramming benefit. It is apt for software engineers, network engineers, tech leads, business consultants and analysts, web designers, UI engineers, students, teachers, and people who need technical diagrams.

With this web-based diagramming tool, you can draw flowcharts, wireframes, mock-ups, UML diagrams, mind maps, info-graphics, organizational charts, and other types of diagrams. You can draw, sketch, and collaborate with this tool.

Creately software

 (Source: Creately)


  • Collaborate with anyone
  • 1000’s of templates
  • Drag-drop to draw
  • Diagrams Anywhere
  • Edit and view
  • Accountability via notification
  • Zoom able and sharable diagram viewer
  • Easy-to-use Interface
  • Offline and Mobile Working
  • Connected Apps
  • Real-Time Collaboration
  • Mind Map
  • Templates and Flowchart
  • Organizational Charting
  • Data Import and Export

5 Calligra Flow (Free and open source)

Calligra Flow is the open source flowchart software that allows the user to enjoy graphical creativity and database designing. This free diagramming and flowcharting application serves as the visual database app creator. It can create network diagrams, flowcharts, and organizational charts.

You can accomplish your work with Calligra Suite that holds the set of applications. Flow is the component of Calligra Office that allows flowcharts. The artists can work on 2D drawings and illustrations by making use of this cutting edge application. Calligra Flow is an easy-to-use app that is tightly integrated with other Calligra applications.

Calligra flow

 (Source: Calligra Flow)


  • Compatibility
  • Integrated Components
  • Standard, Open Format
  • Full Project Control
  • Customizable Dockers
  • Presentation Maker
  • Document Creator
  • Calculation and Spreadsheet tool
  • Vector Drawing
  • Visual Database App Creator

6 Diagramo (Free and open source)

Diagramo is a free and open source diagram tool that features pure HTML 5. No Flash, no Java or other plugins are required to use this tool as it is based only on HTML5.

The software enables users to easily share the diagrams with other teammates or even make it public. You can export pictures in PNG or JPEG format. As per the requirements, the user can customize the app. This online flowchart software provides lifetime support and storage. It is a GPL application so the user can tinker its code and improve it.

diagramo software

(Source: Diagramo)


  • Collaborate
  • Share diagrams with world
  • Pure HTML 5
  • Export to SVG, Gif, and JPEG
  • Lifetime Support and Storage
  • Customization

7 SmartDraw (free, free trial) 

SmartDraw is another easy-to-use and powerful diagramming tool. This free diagram software is the only alternative to Visio that runs on a Mac and Windows. The user can comfortably use this app.

The SmartDraw drawing tool can be inserted into Word, Excel, PowerPoint, Google Docs, and Sheets. On any computer or tablet, the user can run this app. There are perfect layouts in minutes due to the powerful automatic formatting system in this tool. It holds power to make anything.

From flowcharts to floor plans, the user will get all the different types of diagram templates. With standard engineering scales, the user can have true CAD-like drawing abilities. It serves as a breadth of content as it has over 34,000 symbols and over 4,500 templates.

Smart draw

(Source : SmartDraw)


  • Flowchart & Templates
  • Collaborate Anywhere
  • Drag & Drop
  • Mind Map
  • Data Import/Export
  • Templates
  • Organizational Charting
  • Intelligent Formatting
  • Professional Results
  • Integrates with the tools
  • Breadth of Content
  • Import and export Visio
  • Engineering Power
  • Development platform

 8 Inkscape (free and open-source)

Inkscape is an open source vector drawing app that allows the user to create beautiful diagrams. It has tools related to drawing, shape, calligraphy, pencil, and pen. The 3D boxes tool of this app allows quick drawing.

This free app offers custom brushes, design layers, paint tools, stencils, symmetry, and watermarks. Across a wide variety of industries like marketing, branding, engineering, CAD, web graphics, cartooning, individual uses, this application is used by design professionals.  

inkscape software (Source:Inkscape)


  • Object Creation
  • Object manipulation
  • Fill and Stroke
  • Operations on paths
  • File Formats
  • Rendering
  • Text Support
  • User-friendly interface
  • 3D Boxes tool
  • Design layers
  • Auto Shapes
  • Sketch and Trace
  • Easy Export
  • Paint Tool

Hoping you must be familiar with the list mentioned above of promising free and open-source diagram software. There is yet another diagram software which is gaining popularity. The article below will highlight the features of the same.  

Gliffy (popular) 

If you are looking to improve team communication and collaboration, then you can try Gliffy diagram software. For better teamwork, you can drag and drop your way. This versatile tool is easy-to-use. It serves as the online diagramming software that is meant for diagram building, editing, and sharing.

Effortlessly this app can create AWS architecture diagrams, UML diagrams, network diagrams, floor plans, flowcharts, org charts, mind maps, business process modeling notations, Venn diagrams, wireframes, entity-relationship diagrams, and SWOT analysis. It helps businesses of all sizes.

gliffy software

(Source: Gliffy)


  • Collaborate instantly
  • Import-export
  • Preserve and track changes
  • Integrate with Atlassian
  • Share with anyone
  • Diagram with ease
  • Drag and Drop
  • Mind Map
  • Flowchart
  • Organizational Charting
  • Templates

Let’s communicate with diagramming tools!

Diagram Software allows the user to create visual and engaging business documents. It helps in organizing vital information, encouraging understanding, and turning ideas into action.  You can create and develop business plans and processes with these intuitive diagramming tools.

The above-mentioned list of free and open-source diagram software allows users to create flowcharts, mind maps, floor plans, organizational charts, UML diagrams, and network diagrams in the presentations.

In case you want to delve into more advanced features of diagram software, then you can try draw.io, Visio, MyDraw, Simple Diagrams, Edraw Max. If you are using any of the free and open source diagram software discussed in this article, then feel free to share your valuable views on the same.

 If you are looking for other software categories, then click here.

Andrea Hernandez
Andrea Hernandez

Andrea Hernandez is a tech blogger and content marketing expert. She writes about disruptive tech trends counting blockchain, artificial intelligence and Internet of Things. Presently, as a senior writer, she is associated with GoodFirms, a pioneering B2B research, review and rating platform. Follow her on social media for valuable information on the software.

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