How much larger does the file get after encoding?

Base64 adds about 33% to the size — three bytes of binary become four characters of text. A 9 KB PNG becomes roughly a 12 KB data URL. Add a little overhead for the MIME prefix.

Is there a size limit on what I can encode?

The tool accepts files up to 10 MB, but practical limits bite much earlier: very large data URLs (over a few hundred KB) bloat your HTML and can hit length caps in some tools (URLs in older browsers, JSON fields in some APIs). For files over ~50 KB, prefer a real file reference.

Should I encode photos to Base64?

Generally no. Photos are usually 100 KB+, and inlining that much data slows down page rendering and prevents the browser from caching the image separately. Base64 makes sense mostly for icons, logos, and tiny graphics.

Does the encoding preserve transparency and color?

Yes. Base64 is a lossless text representation of the binary file — the resulting image is bit-identical to what you uploaded. If the original PNG had transparency, the decoded image will too.

Will my image be sent to a server during encoding?

No. The browser's built-in FileReader API reads the file into memory and produces the data URL locally. Nothing is uploaded — you can verify in your browser's Network tab.

Image to Base64

Convert an image to a Base64-encoded data URL.

Drop image files here or browse

Max 10MB per file

About Image to Base64

Base64 encoding lets you embed an image directly inside HTML, CSS, JSON, or any other text-based format — no separate file needed, no extra network request. The Convertora image-to-Base64 tool reads a picture from your device, encodes it as a Base64 data URL, and shows you the result ready to copy and paste. Like every Convertora tool, the encoding happens entirely inside your browser, so the image never leaves your device on its way to becoming a string.

This is especially useful when you're inlining a small icon into a CSS file, baking a logo into an email template, sending an image through a system that only accepts text, or testing a component without setting up asset hosting. For larger images you typically want a real file rather than a long string, but for thumbnails, favicons, sprites, and one-off attachments, a data URL is the simplest path from disk to web.

How to use it

1Drop an image into the upload area, or click to pick one from your file system. PNG, JPG, WebP, AVIF, GIF, and SVG are all supported, up to 10 MB.
2Convertora reads the file in your browser using the FileReader API and produces a complete data URL with the right MIME type prefix.
3Preview the image to confirm it decoded correctly, then click 'Copy to clipboard' to grab the full string.
4Paste the data URL into your HTML <img src>, CSS background-image, JSON payload, or anywhere else a regular image URL would go.

What you get

Supports PNG, JPG, JPEG, WebP, AVIF, GIF, and SVG inputs.
Output is a complete data URL with the correct MIME type prefix — paste-ready for HTML, CSS, JS, and JSON.
Live preview shows the decoded image so you can verify the result before copying.
Encoded length is displayed so you can spot when an image is too big to inline efficiently.

Common use cases

Inlining a logo or small icon into an HTML email template that doesn't reliably load external images.
Embedding a sprite or background image in a CSS file to eliminate an extra network request.
Putting a profile picture into a JSON payload when an API expects an image as a string field.
Pasting a quick image into a Markdown document, Confluence page, or wiki without uploading it first.
Generating a self-contained HTML demo or test fixture that works offline without separate image files.

Frequently asked questions

Tips

Compress the image first (Convertora's Compress Image tool) before encoding — a 50 KB JPEG becomes a much friendlier 67 KB string than a 500 KB original would.
For CSS, prefer Base64 only for small decorative graphics. For everything else, a real URL keeps your stylesheets readable and lets the browser cache the image independently.

100% private — runs in your browser

Convertora processes everything on your device using JavaScript and WebAssembly. Files never leave your browser, are never uploaded to a server, and are never seen by us or anyone else. The moment you close the tab, the data is gone — there is no temporary cloud copy, no log entry, no retained backup.

Because the work happens locally, processing speed depends on your device — but there are no rate limits, no daily caps, and no file size restrictions beyond what your browser can handle in memory. No signup, no account, no payment. The tool works the same in incognito mode, on a corporate network, or after the page has loaded once, even with the network disconnected.