DevToolXBase64 Image Converter
Convert between images and Base64 strings with format support
About Base64 Image Converter
Base64 image encoding converts an image file into a data URI — a string of the form data:image/png;base64,… — that can be embedded directly in HTML, CSS, or JSON without an external file reference. The browser treats it as a normal image source. This tool handles the encode/decode round-trip and auto-detects the MIME type so you get a standards-compliant URI ready to paste.
Common Use Cases
Frequently Asked Questions
Is there a recommended size limit for Base64 images?
Keep them under 10 KB. Larger images inflate page size significantly — Base64 adds roughly 33% overhead — and block the browser from caching the image independently. For anything bigger, host the file and reference it by URL.
Why does Base64 encoding inflate file size by ~33%?
Base64 encodes every 3 bytes of binary data into 4 ASCII characters. That 4/3 ratio is the source of the overhead. A 9 KB PNG becomes approximately 12 KB as a Base64 string.
How are data URIs supported across browsers?
Data URIs are universally supported in all modern browsers and have been for over a decade. They work in img src, CSS background-image, and JavaScript blob operations without any polyfill.
When should I use inline SVG instead of Base64 PNG?
If your image is already an SVG, inline it as raw markup (the <svg> element) rather than Base64-encoding it. Inline SVG is smaller, stays in the DOM for CSS manipulation, and scales without quality loss. Base64-encode only raster formats (PNG, JPEG, WebP) where inlining raw bytes is not an option.
How does this tool detect the MIME type?
It reads the file's magic bytes (the first few bytes of the binary) to identify the format — for example, PNG files start with the bytes 89 50 4E 47. This is more reliable than trusting the file extension.