Free online MERMAID to PNG converter

PNG is useful when a Mermaid diagram must be inserted into a document, presentation, issue tracker, or image-based archive that cannot render Mermaid source. Converting the diagram also creates a fixed visual snapshot for sharing, while the original Mermaid file remains editable.

What the MERMAID format is

A MERMAID file is a plain-text diagram definition, commonly saved with the .mermaid or .mmd extension. It contains Mermaid syntax for flowcharts, mind maps, sequence diagrams, class diagrams, state diagrams, entity-relationship diagrams, and other structured graphics rather than stored pixels.

Mermaid files are created or edited in the Mermaid Live Editor, Mermaid CLI, Visual Studio Code with Mermaid extensions, and applications such as Obsidian, GitLab, and GitHub that support Mermaid rendering. You may encounter one when a diagram is stored in a source-code repository, Markdown document, notes application, or documentation project.

What the PNG format is

PNG is a raster image format supported by web browsers, office software, presentation tools, image viewers, and most document systems. It uses lossless compression, preserves sharp solid-color lines and text better than JPEG, and can store transparent backgrounds.

PNG is suitable when the recipient needs an ordinary image rather than Mermaid syntax. It is not ideal for editing individual diagram elements or for extremely large diagrams, because enlarging a raster image can make text and lines appear pixelated.

How to convert MERMAID to PNG

Using 101convert online

1. Open the MERMAID-to-PNG converter on 101convert.com.
2. Upload the .mermaid or .mmd file.
3. Start the conversion and download the generated .png file.

This option requires no installed software and is suitable when the Mermaid file does not contain sensitive information.

Using Mermaid CLI

For repeatable local conversions, install Mermaid CLI with Node.js:

npm install -g @mermaid-js/mermaid-cli

Render a source file with:

mmdc -i diagram.mermaid -o diagram.png

The input can also use the .mmd extension. To increase raster resolution, apply a scale factor:

mmdc -i diagram.mmd -o diagram.png -s 2

Use a background color when transparency is unsuitable:

mmdc -i diagram.mmd -o diagram.png -b white

Mermaid CLI renders the source with a headless browser. If installation reports a Chromium or browser problem, follow the Mermaid CLI version's browser setup instructions before rerunning the command.

Using a diagram editor

Open the source in the Mermaid Live Editor or another Mermaid-compatible editor, check that the preview renders correctly, then choose Export → PNG or the equivalent image-export command. Export settings may allow a transparent background, theme selection, or scale adjustment.

Quality and compatibility considerations

The PNG reflects the Mermaid renderer, Mermaid version, theme, available fonts, and any initialization settings used during export. A diagram can therefore look different when rendered by another application or version.

Increase the export scale for diagrams containing small labels; changing the PNG width after export does not restore lost detail. Keep the original Mermaid source with the PNG because PNG does not preserve nodes, links, layout rules, or editable text.

If the destination supports vector graphics, SVG is usually better for large diagrams and later resizing. Choose PNG when the target application accepts raster images only or when a fixed-size image is required.