1. Dia
Dia is a free and full-featured flowchart app. It’s also entirely open source under the GPLv2 license, which is great if you believe in the open
source philosophy. It’s powerful, extensible, and easy to use.
If you’re looking for the best free alternative to Microsoft Visio, then Dia is as close as you’re going to get.
Key features and highlights:
• Simple and intuitive interface.
• Dozens of standard shapes, including UML, circuit, and database.
• Add custom shapes using XML and SVG.
• Colorize shapes and text with standard or custom colors.
Download: Dia (Free)
2. yEd Graph Editor
yEd Graph Editor is an excellent, up-to-date tool for flowcharts, diagrams, trees, network graphs, and more. You can download the app as a JAR
file (which requires Java on your system) or an EXE (which includes a Java installer). It’s powerful and versatile, but the trade-off is an ugly,
Swing-based interface.
Key features and highlights:
• Very little effort for professional-quality charts.
• Auto-arrange flowchart elements from messy to clean.
• Organic and orthogonal edge routing for connections.
• Several export options, including PNG, JPG, SVG, and PDF.
Download: yEd Graph Editor (Free)
3. ThinkComposer
ThinkComposer is a tool for professionals. In addition to flowcharts, it can handle business models, class diagrams, genealogy trees, timelines,
use case diagrams, and more. It’s a bit overkill for one or two charts every so often, but a smart choice if you deal with flowcharts on a daily or
weekly basis.
Key features and highlights:
• Create custom, reusable nodes and connections.
• Deep, multi-level diagrams for full visual expression of ideas.
• Compositions can combine many different charts and graphs.
• Generate PDF, XPS, or HTML reports based on your data.
• Open source and extensible with plugins.
Download: ThinkComposer (Free)
4. Pencil Project
Pencil Project is an old app that fell out of favor due to a long development hiatus, but things picked back up in 2015 and version 3.0.0 was
released in 2017. Everything is now modern and up-to-date, making it an excellent choice for anyone who needs fast, simple diagramming with
a minimal learning curve.
Key features and highlights:
• Tons of built-in shapes for all types of charts and interfaces.
• Create your own shapes or install collections made by others.
• Several export options, including PNG, SVG, PDF, and HTML.
• Import art from OpenClipart.org for use in charts and diagrams.
Download: Pencil Project (Free)
5. LibreOffice Draw
LibreOffice is arguably the best free alternative to Microsoft Office for word processing, spreadsheets, presentations, and even visual diagrams.
With LibreOffice Draw, you can easily add shapes, symbols, lines, connections, text, images, and more. It isn’t perfect, but it’s certainly flexible.
Key features and highlights:
• Custom page sizes, great for all kinds of chart types.
• Page map makes it easy to work on multiple charts.
• Advanced object manipulations, including 3D controller.
• Can open (but not save to) Microsoft Visio format.
Download: LibreOffice (Free)
6. Diagram Designer
Diagram Designer is somewhat primitive, and that’s partly because it hasn’t been updated since 2015. But don’t let that turn you away! It runs
fine on my Windows 10 setup, and it’s more than effective for creating flowcharts that look nice. Could it be better? Of course. But for personal
use, it’s great.
Key features and highlights:
• Easy-to-use drag-and-drop interface.
• No unnecessary features that steepen the learning curve.
• Import and export PNG, JPG, BMP, GIF, ICO, and more.
Download: Diagram Designer (Free)
7. PlantUML
PlantUML is unlike all the other apps in this list. Instead of a graphical interface, you create your diagrams using PlantUML’s scripting
language. This is an excellent tool for programmers who don’t like mouse-based drag-and-drop. PlantUML requires Java on your system.
Key features and highlights:
• Define objects and relationships using PlantUML’s scripting language.
• Supports many diagram types: sequence, usecase, class, Gantt, etc.
• Export diagrams as PNG, SVG, or LaTeX.
Download: PlantUML (Free)