Why is Base64 bigger than the file?

Base64 uses 4 characters for every 3 bytes, so it adds about a third. Gzip on your server wins some of that back.

When should I inline an image?

For very small icons and placeholders, under a few KB. Larger images are better as normal files, so they can be cached.

SVG is already text, so encoding only a few characters beats Base64 in most cases and compresses better too.

No. Encoding happens in your browser with WebAssembly, so nothing is sent to a server.

Image to Base64

Get a Base64 string or data URI, ready to paste into CSS, HTML or JSON.

Runs on your device. Nothing is uploaded.