Decision guide · Export formats
Mermaid SVG vs PNG: Which Should You Use?
Both formats come from the same Mermaid source, so this is not a quality contest — it is a compatibility question. SVG is vector: infinitely sharp, small for node-and-edge diagrams, but not accepted everywhere. PNG is raster: heavier and resolution-bound, but it displays on every platform ever made. The decision comes down to where the diagram will live.
No signup · No watermark · Local browser rendering · Export both formats from the same source
The short answer
Use SVG when the diagram lives in documentation: docs sites, wikis, GitHub READMEs, and anywhere readers zoom in. Text stays sharp at every size and the file is usually smaller than a high-resolution PNG. Use PNG at 2x when the destination is a slide deck, chat tool, email, ticket, or any platform that rejects or mishandles SVG uploads — Google Docs and Notion inline images among them. If the diagram travels to more than one place, export both: keep the SVG as the canonical copy and share the PNG.
Decide in four questions
- 1
Where will the diagram live?
Documentation site, wiki, or GitHub README: pick SVG. Slides, Slack, tickets, or email: pick PNG at 2x. That single question settles most cases.
- 2
Does the platform accept SVG uploads?
GitHub renders committed SVG files in Markdown, and most docs generators serve them fine. Google Docs rejects SVG entirely, Notion treats uploads as attachments, and many chat tools show them as files instead of images — those need PNG.
- 3
Will readers zoom or resize it?
Dense architecture and ER diagrams get zoomed. SVG handles that natively; if you are stuck with PNG, export at 4x so the detail survives magnification.
- 4
Unsure? Export both
Keep the SVG next to the Mermaid source as the canonical, always-sharp copy, and generate a 2x PNG whenever a platform refuses the SVG. Both come from the same code in one paste.
Export your diagram here
Paste your Mermaid code below, pick a style, and download the image. Everything renders locally in your browser — no signup, no watermark.
Export controls activate after your diagram renders locally.
Strengths at a glance
Sharp at any zoom and screen density, small files for typical diagrams, inspectable text markup that plays well with version control. Weakness: inconsistent upload support outside docs platforms.
Displays everywhere: office suites, chat, email, issue trackers, CMS uploads. Export at 2x for docs and 4x for slides so resizing does not soften labels. Weakness: fixed resolution and larger files.
JPG compresses diagrams poorly (text gets artifacts) but some legacy systems require it. WebP saves bandwidth for web embedding. Reach for these only when the platform demands them.
FAQ
Questions about this workflow
Which format is better for a GitHub README?+
SVG. GitHub renders committed SVG files inline in Markdown, the text stays sharp at every zoom level, and the file is typically smaller than a 2x PNG of the same diagram. Use PNG only if the README is mirrored somewhere that mishandles SVG.
Which format should I use for PowerPoint or Google Slides?+
PNG at 2x or 4x. Slide tools handle raster images predictably, and a transparent-background PNG sits cleanly on branded slide layouts. SVG support in office tools is partial and renders inconsistently.
Do both formats support transparent backgrounds?+
Yes. SVG is transparent wherever no background is drawn, and PNG preserves alpha transparency. JPG does not support transparency at all — it fills the background with a solid color.
Why is my PNG file so much bigger than the SVG?+
PNG stores pixels, so file size grows with resolution — a 4x export is sixteen times the pixel count of 1x. SVG stores shapes and text, so size depends on diagram complexity, not display size. For typical flowcharts, SVG is the smaller file.
Which format prints better or exports to PDF cleanly?+
SVG, where the pipeline supports it — vectors print sharp at any DPI. If the document tool only embeds raster images, use a 4x PNG so the diagram holds up at print resolution.