Free online PUML to PNG converter

Source format: PUML

PUML is a text-based file used to describe diagrams for PlantUML. It is commonly written by software developers, system architects, and technical writers to create UML diagrams, flowcharts, sequence diagrams, class diagrams, and other documentation visuals from plain text. Because it is human-readable, a PUML file is easy to edit in a code editor and works well in version control systems.

Typical use cases include documentation generation, design reviews, architecture diagrams, and embedding diagrams into developer workflows such as CI/CD pipelines or documentation builds.

Target format: PNG

PNG is a widely supported raster image format that uses lossless compression. It is ideal for diagrams because it preserves sharp lines, text, and transparency better than many other image formats. PNG files are easy to view in browsers, insert into documents, share in presentations, and publish on websites.

For diagram exports, PNG is especially useful when you need a static image that can be opened almost anywhere without special software.

How to convert PUML to PNG

The most reliable way to convert .puml to .png is with PlantUML. You can also convert the file on 101convert.com for free, without installing any software.

Method 1: Using PlantUML locally

1. Install Java and download the plantuml.jar file.
2. Make sure your PUML file is valid and saved with the .puml extension.
3. Run PlantUML from the command line in the folder containing your file:
   java -jar plantuml.jar diagram.puml
4. PlantUML will generate a PNG image with the same base name, such as diagram.png.

If you want to convert multiple files at once, place them in one folder and run PlantUML on that folder. It will render each valid diagram into a separate PNG file.

Method 2: Using a desktop editor with export support

Many PlantUML-capable editors and IDE plugins can render and export diagrams directly. In such tools, open the PUML file and use the export or save-image command, often found under File → Export or a similar menu. The exact menu name depends on the editor.

Method 3: Using the built-in online converter

If you do not want to install software, upload the PUML file to the converter on 101convert.com, choose PNG as the output format, and start the conversion. This is convenient for quick one-off conversions.

Notes on quality and limitations

PNG is lossless, so diagram lines and text remain crisp. However, PNG is a raster format, so very large diagrams may become less convenient to zoom compared with vector formats such as SVG or PDF. If you need scalable output for printing or documentation, consider exporting to a vector format instead.

Conversion quality depends on the correctness of the PUML source and the fonts available on the system. Missing fonts or unsupported PlantUML syntax can affect the final image. Also, if the diagram is very wide or tall, you may need to adjust PlantUML settings such as page size, scaling, or layout directives to get a readable PNG.